What is this on his belly??

[Cham]

I don't know if that is a burn or not(someone else can chime in on that), but my first questions are:

Are you using a UTH?

Are you using a thermostat?

Do you have a thermometer?

Yes I'm using a thermometer and the temp is all right but I'm worried that is has to do with the uth.. He likes to push all the bedding away so he lays on the glass over the uth (yes I have the uth under the terrarium) and maybe it gets too hot?