The wrinkles look more like he's a little dehydrated. I don't see stuck shed in your photo. If there is some stuck shed somewhere (and it could be I'm just not seeing it) you can soak in the warm tub as long as 45 minutes-an hour, just make sure the water stays warm and that he has a place to rest his head if he gets tired. You don't need much water, he looks like a fairly small guy. I drop a washcloth or small towel in there with him so he has something to rub on.
How long should i keep doing this? Should i put a moist hide in there also?