I do rinse it every two/three days with fresh water and scrub it when I spot clean weekly. The bowl is under the heat lamp, not directly but I just noticed the water is somewhat warm. I usually do this to cause evaporation=humidity but maybe the water is too warm for his liking? I do see him drink after he eats but I don't know. Maybe because he is all black these lines where he is folding his skin show more? I just never noticed it on patterned ball pythons. I feel like after a big drink they seem to go away but this could be from stretching out and not being balled up. I'm probably just over thinking the situation. He eats, sheds, defecates fine so Im not overly concerned. His eyes are not dented so he's not dehydrated. I feel like his skin is just "dry" which in turn causes the wrinkles.