The loose skin is often a sign of dehydration. To be safe, shower him. He does seem to have some patchy skin on his head and back - so that is very likely a possibility.
I dont' think he's that fat - and I'm quick to call a fat chameleon! The meat onf his casque isn't bulging, and wiht pardalis, that's a good sign. Also, his feet seem nice and defined, not like fat boxing gloves.
Get some fluids into him, and see if the wrinkles go away.