Constant stress marks?

Hi! I have posted a few times about my baby Po. He is 4 months old now and i’ve had him for about 2 months. Ever since I got him, he most of the time has stress marks and is a darker shade (which i have read is a sign of stress). There are a few times i have seen him in the tank where they have been gone and he is a bright orange color like he should be, but mostly he is darker and they are there. He is in a 20 gallon long tank (he’s only about 8 inches) and has a paper towel substrate. I have a reptisun T8 10.0 UVB diagonally lates across the tank. The cool side is about 70-72 degrees and the basking spot is 98-100. I have read that babies should be kept at warmer temps but my breeder insisted that this is the correct temperature and that any higher would be too hot and cause him stress. In addition, when he arrived i was instructed to place white paper around the sides of his tank to help him better settle and slowly remove them as he settles in. I have removed most of them, and there are only 3 pieces around the sides still there. He seems to stare at himself and me in the places that he can, and in the mornings i can hear him sprinting frantically around the sides of the tank. I also remove any uneaten bugs right away so that couldn’t be it. Any idea what could be stressing him out??

Hello,

Do you have pictures of him along with the tank setup we could see?
What type of thermometer are you using, a digital probe or a temp gun?
The tube bulb should be 6-8 inches from your dragon, alongside of the basking light. Is it placed
on top of a screen top or without a screen top?
How much food is he eating?
It is possible it could be too hot, since he is in a 20 gallon tank. Let us know what type of thermometer you are using because if you are using a round analogue type, they can be off by as
much as 10-20 degrees in some cases.

Tracie