I think a stuck shed is the least of your worries. A stuck shed would never look lumpy like that. It usually does the exact opposite and makes the snake look wrinkly and dehydrated. I know there are a few different kinds of things that can cause blistering, but I have never seen blisters severe enough to look that way. It almost looks like those are pretty far beneath the skin like maybe in the muscle tissue or right on top of it. I have to try to diagnose alot of stuff at work before we take them to the vet, but this one is tough for me...