Possible Belly Rot?

[Ladybugzcrunch]

I keep a newsprint layer with a substrate layer to separate his stomach from having direct contact on the bottom of the glass to prevent harm. Should I still get a regulator though? I also keep a light overhead on the outside of the cage on the warm end.

You still need to regulate the temps, they can a will get too hot. Looks like rot to me though. Were mine I would take him to the vet and get those UTH's on a t-stat or at least a dimmer.