No problem. burns are on the surface just like you burn so the question is does it look like it is a surface thing or under inside the snake it is hard to tell from photos you need to decide that for yourself. If you think it is a surface thing it is time for a visit to a vet or knowledgeable person in your area. If it seems to be under the skin and scales like a red pea in a white balloons it is likely organs you are seeing.

I like 92 as a max and often set to 91 or 90 as it keeps things well with in normal temps even in case of thermometer error. I have a good thermometer (lab grade) but use the cheapest ones I can find and buy 5 and check them against each other usually 3 will be very close with one off a bunch and one off some. I get rid of the poor ones and use the best two and the third as a back up. I toss them when they go off. (8 months they seem to go screwy.) I am admittedly OCD as I test all of them every 6 months...