What kind of watering do you provide? automatic misting? dripper? hand misting? how often and for how long? His eyes do seem sunken..... but maybe not in a bad way. My cham Fred seems just fine but his eyes don't bulge like my other male Jake. Take a look at his urates to get a better idea of his hydration. If they are white then he is fine. If you are getting yellow or orange urates he is definitely dehydrated. He does look good in general. What do you feed him?