Does anyone know what this could be?

[Skiploder]

For any one thinking that this could be either a contact or other type of burn, please share with us of your experience in dealing with necrotic, vesicular or ulcerative dermatitis that presents dorsally/laterally and/or heat lamp burns that occurred without direct contact to a heat source.

Please explain how thermal burns from a heat lamp result in various raised blisters along the dorsal side and the flanks of the snake.

While I can't really rule out anything, I'm also not throwing guesses into the wind. The message here should be to encourage the OP to go to a vet and to encourage him to have a necropsy done.

For all those people who think it's a burn, did you ever suppose for a minute that the attending vet would have recommend euthanasia if those were burns? Even severe burns in reptiles are fairly easily treated with silver sulfazidine, antiseptic baths and sterile cage conditions.

When reptiles suffer thermal burns, they present in several ways depending on the severity of the burn.

What I would classify as first degree burns are largely superficial. First degree burns in reptiles rarely, if ever, blister. The skin reddens and sometimes bruises. These are very easily treated and a vet would not recommend that the animal be put down for these burns. No way, no how.

A more severe or second degree burn in a snake does result in blistering - but also fairly significant oozing. There is widespread discoloration from bruising and color changes in the epidermal layers. The blistering from a second degree burn does not present without discoloration to the edges of the burn. The blisters shown in the photos do not support second degree burns.

In the most severe burns, whatever skin is left turns either black or white. I have never seen blistering associated with third degree snake burns. They always looks like the skin has been either charred or melted off of the animal. There is also a lot of discharge associated with these burns.

Burns from overhead heating sources are extremely hard to contract unless the animal has contact with the source. If it's an external heat lamp as the OP has described, contact burns could conceivably come from the superheated screen on the enclosure (if used), but those burns would present in a pattern and size consistent with the pattern on the screen, not a series of raised, cutaneous swellings on the snake. As some of those burns occurred on the sides of the snake, it would make direct contact burns with an overhead heat source even more difficult to explain.

Now what I have seen are fungal infections in both captive and wild snakes that present in many ways - as subcutaneous reddened nodules, as separations of the outer layer of skin from the inner layer (patches that redden and then separate).....etc.

However, what I'm NOT going to do is throw guesses at the OP. Unless the attended vet was complete idiot, I would find it hard to believe that he would recommend euthanasia for either thermal burns or blister disease.