Have you recently changed or added anything in his enclosure? Awhile back I put larger hides in my adults tank and barely a day later he was in the water bowl. He would put his head and neck in the bowl and coil his body up on top with only his nose poking out. After 2 weeks of checking for mites, temps/ humidity, and signs of shedding I thought maybe he just doesn't like the hides. I put the smaller ones back in and about an hour later he was back where he belongs...
Do you have any pics of the enclosure? And you titled the thread "Redish, pinkish,belly." If you are certain he isn't going into shed, what do your temps look like and what did you use to wash out the tank?
Rob