Does anyone know what this could be?

[Skiploder]

If you still think it was something other than a burn, I'd actually love the information so I can provide it to the vets where I work. I had to tell them about the spider wobble (we had one in from a pet store), and about stargazing in corns (brought in my 'gazer so they could see the corkscrewing he does) and they're always interested in learning more about reptile diseases that don't get much study in academic papers.

Without seeing the snake and looking at it's "blisters", it could be a couple of things.

I've had imported animals come in with fungal dermatitis that presented as raised red blisters and separated skin - eventually concluding with crusty lesions. They have been successfully treated with antifungals targeted at the causative agents.

I've also seen reddened fluid filled bumps form on the ventral and lateral sides of female snakes that I swore were skin disease but which turned out being oviduct infections that were oozing fluid into the subdermal areas adjacent to the ova.

That's why assuming it's something is fruitless. The direction should be toward a qualified herp vet and a necropsy or histological sample if applicable. Then a definitive diagnosis can be made and if these results are shared with the community, the community becomes wiser.