I'd say a burn I'm not a vet nor claim to be so I haven't seen any solutions so I'll give it a shot. First a thermostat a must till u get your hands on one if a Heat pad apply cardboard inside glass of tank. This is NOT a solution a thermostat is.
The burn itself does not look terrible so do the following betadine solution to water in small tub with top enough to cover 3/4 of its body 1 time daily. Just enough in warm water to turn it reddish a touch. Then add silverdine cream twice daily.. Do for a week next shed you should be good.
This is the method that The late Bob Futo taught me and he forgot more about snakes than I or most will ever know.