Could be a few different reasons..
If there's a possibility you over fed him, you can help him by putting him in a sink of warm water that's chest high, for about 10 minutes. But stay with him with your hand in the water if he needs to lean on it. Usual symptoms are dragging rear legs.
Also, it could be if under or over supplemented. But he would be shaky and have a hard time aiming for crickets.
If you remember dropping him by accident it could have injured his spine. They're quick and accidents happen! Posting his age, diet, supplement schedule, lighting, will help pinpoint any problem and help correct it!
Concerning superworms, I err on the side of caution and don't feed them too many or every day. Usually 4-6 of them every other day when a young adult, on the side of the rest of their diet. The chitin in them takes time to digest and can bind if they become dehydrated.
Freshly rinsed greens and veggies, every day will help that. If he's not eating anything with moisture, dehydration copuld play a role in the problem. Also, with warmer months here have you watched the temperature's in your tanks well, because just one high heat day can cause neurological disorders.
Sprinkling the veggies in an empty bowl in the tank, daily will get his attention. He may eat them when he runs out of good stuff. Most problems start with husbandry, so work on that, get the info out here for us to help where we can!
Good luck!
