Ouch! This excerpt (-from https://www.petmd.com/reptile/emerge...ns_in_reptiles ) might help? I've never had to treat any of my snakes for burns,
and I don't know how serious your snake's is just by looking at your photo. I do know that a "larger than usual meal" does not cause a burn, your set-up needs improvements
TREATMENT
Burns may be quite serious if proper attention is not given immediately. The breaks in the skin caused by burning can leave your reptile at risk from bacterial and fungal infections, which can quickly become systemic and life threatening. It is difficult to determine how deeply tissue has been burned, therefore, taking your reptile to a veterinarian to get supportive care is essential. Veterinary treatment can include antibiotics, pain management for the burns, and feeding techniques for the the animal, who may have lost a lot of fluid.
The burned area will need to be cleaned and treated with topical ointments and/or cleansing baths. Your veterinarian may prescribe daily povidone-iodine soaks and an antibiotic ointment specifically for healing burned skin.
In cases of severe burns, a lot of fluid can be lost, leading to severe dehydration. The reptile may need fluids that can be given by enema or via injections. Your veterinarian will guide you in the best ways to help your reptile to heal from the burn.