I just saw your photo/post, and can you please clear up a few things?
First of all, how long have you had her? She does look to be probably around 9-10 months or so, from what I can see of her, but depending on how long you've had her will tell you whether or not you need to replace her
UVb light...you said you have a "Reptisun 10.0 long bulb", do you mean a long tube, at least 18" long that fits into a long, 18" tube fixture, or do you mean the longer bulb that fits into a regular lightbulb socket? I can't tell from your photo...
I think I see a long tube fixture at the back of your tank...if so, that's good because it means you at the very least have an 18" Reptisun 10.0 T8 UVB tube...The problem you have, which is serious, is that it's most likely the much weaker T8 strength UVB tube (instead of the much stronger T5 version of the UVB tube), and as such, there are some very important rules you have to follow when using the weaker T8 strength UVB tubes:
1.) T8 strength UVB tubes must be replaced every 6 months at the oldest, like clockwork, because they have a very fast
UVB light decay-rate, and at 6 months old they stop emitting any
UVb light. So even though they don't burn out and will still emit light, they don't emit any
UVb light at all. That's why I asked you how long you have had her, since you said that you bought the UVB tube when you got her.
2.) You cannot sit a T8 strength UVb tube on top of a mesh lid at all, they must be mounted inside the tank and underneath the mesh lid. Metal mesh lids to tanks block around 40% of the
UVB light emitted by the UVB tube, and the T8 UVB tubes are far too weak to still penetrate adequate
UVB light to your dragon on the other side of the mesh lids. So you have to poke holes in the mesh lid with tin-snips or a Utility knife and then use long, plastic zip ties, wire, twine, shoelaces, etc. to strap the entire UVB fixture to the underside of the mesh lid.
3.) Your tank is a "tall" tank, and as such, even if you had the UVB fixture strapped to the underside of the mesh lid, which you do need to do ASAP, the weaker T8 UVB tubes must be within at the very least 6" of his main basking spot/platform. I can't tell how tall your tank is, but it's not a "long" tank, it's definitely a "tall" tank, so once you get the UVB tube fixture strapped to the underside of the mesh lid, you need to measure how far away the actual UVB tube up inside the fixture is from the exact spot that your dragon sits while basking. If it's not within at least 6", you'll need to find/make him a higher basking spot/platform that will put him within at least 6" of the actual UVB tube up inside the fixture.
Make sure that your UVB tube fixture has a Metal Reflector inside it, behind where the UVB tube sits. This is crucial to reflecting
UVB light throughout his tank, especially a tall tank.
You seem to be using a stick-on thermometer, and you cannot measure his Basking Spot Temperature with a stick-on thermometer (it's a Surface Temp, and stick-on thermometers can only measure Ambient temperatures). If you don't have one already hiding somewhere, you need to spend $10 at Petco/Petsmart or any pet shop on a Digital Thermometer that has a Probe on a wire. They are not only way more accurate than any stick-on thermometers (they are often off by between 10-20 degrees when tested), but you can sit the probe right on his basking spot/platform once you get the lights set up properly, let it sit there for at least 20-30 minutes, and then read the Basking Spot Surface Temperature, which for a dragon under a year old needs to be between 105-110 degrees F...this needs to be very accurate, you cannot estimate what the 3 temperature zones inside his tank are, this is crucial to his digestion, absorption, and processing/usage of any and all nutrition he takes in.
You don't have his tank quite set-up properly, but once you get a new replacement T8 UVB tube and a Digital Probe Thermometer, this is your opportunity to get his tank set up properly.
There should be 2 sides to his tank, a "Hot Side" which contains his Basking Spot/Platform within it, and then a "Cool Side", which is opposite the Hot Side. As such, there are 3 temperature zones inside a dragons tank: the Basking Spot Surface Temperature (between 105-110 degrees F under a year old, between 100-105 degrees over a year old), a Hot Side Ambient (air) Temperature (between 88-93 degrees F maximum), and a Cool Side Ambient (air) Temperature (between 75-80 degrees F maximum).
Your main goal to getting his lighting set up correctly is to replicate natural sunlight as closely as possible, and additionally, to get these 3 temperature zones within the correct temperature ranges, so that he has a Basking Spot Surface Temperature that is hot enough that he can properly digest his food and absorb the nutrition from it, a Hot Side Ambient Temperature that is still very warm and will keep his metabolism up and processing his nutrition, but that is not nearly as hot as the Basking Spot Surface Temperature, which they usually only sit on right after they eat, and then finally a Cool Side Ambient Temperature which is considerably cooler than the other side of the tank that he can go to at any time to cool off. These need to be precise temps and that's why you cannot rely upon stick-on thermometers, besides the fact that you cannot at all measure his Basking Spot Surface temperature without a Probe or a Gun.
The other major issue you have is how you have your lights set-up, As I already mentioned, your main goal is to replicate natural sunlight as closely as possible over his Basking Spot/Platform, and you do this by PUTTING BRIGHT WHITE LIGHT (and heat) AND
UVB LIGHT BOTH DIRECTLY OVER THE HOT SIDE OF THE TANK, AND PUTTING HIS BASKING SPOT/PLATFORM DIRECTLY UNDERNEATH BOTH LIGHTS.
When you go to poke the holes in the mesh lid and strap the UVB tube fixture to the underside of the mesh lid, you need to make sure that you put both the UVB tube fixture and then your Deep Dome fixture that contains your bright-white Basking Bulb RIGHT ALONGSIDE EACH OTHER, and both over the Hot Side of the tank. You can't have the UVB tube in the center of the entire tank (not an 18" tube anyway) or against the back or front of the glass, but rather, place the UVb tube fixture off-center inside the Hot Side of the tank, and then sit the Deep Dome fixture that contains the Basking Bulb off-center over the Hot Side of the tank as well, so that both lights are right alongside each other, not end-to-end, but rather right side-by-side over the Hot Side of the tank. So be sure that you make the holes in the mesh lid in the proper place of the lid: Over the Hot Side of the tank, and leaving enough room for the Basking Bulb to sit right alongside it on top of the mesh lid, basically you'll have both lights meeting in the center of the Hot Side of the tank.
Once you get the UVB tube mounted underneath the mesh lid and get the Basking Bulb set up right next to it, both lights right alongside each other and over the Hot Side of the tank, then you need to move his Basking Spot/Platform so that it is directly underneath both lights, SO HE GETS BOTH LIGHTS AT THE SAME TIME WHILE HE'S BASKING. Remember that the Basking Spot/Platform will need to be high enough so that it puts him within at least 6" of the T8 strength UVb tube.
After you get both lights set up correctly (UVB tube strapped to the underside of the mesh lid), then you need to take all 3 temperatures, being sure to allow the Probe of the thermometer to sit on each spot for at least 20-30 minutes before reading the temperatures. To measure the Hot Side and Cool Side Ambient temps, use the suction-cup that comes with the Digital Probe Thermometer. Attach the suction-cup to the wire, just below the Probe. Then you can stick the suction-cup to either the front or the side glass of the tank on the Hot Side and then the Cool Side of the tank, respectively, to measure the Ambient temps. Place the suction-cup about 2" up from the floor of the tank to measure the 2 Ambient temps, allow the Probe to hang there for at least 20-30 minutes, and then read the temps.
You may have to (probably will judging by what you're already doing) either use a higher wattage of bright-white colored Basking Bulb over the Hot side to get the Basking Spot Surface Temp between 105-110 degrees and the Hot Side Ambient (air) Temp between 88-93 degrees. You'll find out once you use a proper Digital Probe Thermometer to measure both temperature zones once you get the lights set up properly. You can always use a regular, household, Halogen Indoor Flood Bulb as the Basking Bulb, they are all bright-white in color and cheaper. Start with a 100 watt one and go from there.
Once you get both the Basking Spot Surface Temp and the Hot Side Ambient Temps within the correct ranges, you may have to add a second bright-white Basking bulb over the Cool Side of the tank in either another Deep Dome fixture or you can simply buy a cheaper clamp lamp with an aluminum reflector at any Walmart. They sell 3 different sizes, the middle one is either a 6" or an 8" and works very well, and only cost $6.50 at Walmart in the aisle that has all of the electrical wiring supplies, breaker boxes, switches, etc. This second bright white basking bulb will be much, much lower wattage than the main Basking Bulb over the Hot Side, all you are trying to accomplish by adding this second basking bulb over the Cool Side is to get the Cool Side Ambient Temperature between 75-80 degrees F, and also brightening up the Cool Side of the tank too, so it's not so dark. I have a large, glass Exo Terra with a mesh lid and front-opening doors, it's not as tall as your tank so it's easier to get the UVb tube within the correct range from the Basking Spot/Platform, but I use a 100 watt Halogen Indoor Flood Bulb in a Deep-Dome fixture over the Hot Side, right alongside a 22" Reptisun 10.0 T5HO UVB tube that can sit on top of the mesh lid (the much stronger T5 UVB tubes can sit on top of the mesh lids, as opposed to the much weaker T8 tubes), but I still needed to add a secondary bright white Basking Bulb in one of those clamp lamps over the Cool Side to get the temperature to 75-80 degrees, and to brighten the Cool Side of the tank. I added this after I got the Hot Side of the tank and it's temps set up correctly, and I think I only have either a 30 watt or a 40 watt Halogen Indoor Flood Bulb over the Cool Side. Works perfectly and brightens the tank up.