That looks like MBD to me. Notice also the position of his arm. His bones are like rubber and he can't control his muscles well from lack of vit D3. What are you using for uvb? Coil or tube and what brand. 8" is not going to be enough with a screen so depending what you are using I can make a suggestion. Age of the bulb is also a factor. I would get him some liquid calcium and take him outside for real sunshine. He is too young for superworms and they really should be a treat more than a staple. You can try black soldier fly larvae, roaches or crickets. You should not use loose substrate. Papertowels, tiles or non-adhesive shelf liner works fine. You should be using a thermometer that has a digital with probe or a temp gun. Are you using the stick on thermometers because those are not accurate. The probe needs to be on the basking spot and should be 100-105 and the cool end 75-85. They need calcium and proper amounts of ultra violet light (from your uvb or real sun outside) in order for their body to process the vitamin D3 they need. He is suffering the way he is now but you can turn this around. Some things like his arm bent may be permanent but you can make him better and feel better. He also still has time to grow once these corrections are made.
This is what I would do:
Get some liquid calcium
Get the right insect foods, you can also offer turnip/dandelion or mustard "greens", shredded squash and carrots.
Get a proper UVB or mount it correctly. VERY important that we know what you have.
Take him outside for 30min+ daily for real sunshine.
Change the substrate
Make sure the basking spot is lower since he can't move onto higher spots.
Edit:
I should also ask, was this sudden because I supposed it could of been from injury also?