So I take it you don't know what the tanks temps are over the UTH? You need to find out what the temps are in the tank. Turn off the UTH immediately if you still have the snake in this tank. Use overhead heat until you can clear up any problems in the tank as well as the snake. If you want quality help, a picture of the injury is needed as well as the tank the way it was set up when you noticed the burn.

Good Luck!
Jim Smith