That's what I thought too when I saw the pictures. Scale Rot can take a little while to get that bad, with a snake sitting in a dirty/wet cage for a few weeks. If you noticed it just "appear" then it sounds like a burn. Definitely use a thermostat if you use a heat pad (but I think you said you removed the pad).
Soaking in Betadine will help protect against infection (mix it with tepid water until it looks like dark tea). Just make sure you dry the snake well before putting Neosporin (with OUT pain reliever) or Silvadene on the wound. You want to keep any moisture to a minimum. If you treat the snake at home and if in a few days it looks to be healing and not infected (no puss, redness or swelling) it should be ok. I would still follow up with a Vet as soon as you can.
PS - Good, knowledgeable herp vets can be hard to find. I hate to say it but sometimes taking a reptile to a vet can do more harm than good.