tttaylorrris spot-on, get that heat mat regulated before the snake goes back into the tank. Also, paper towel is the only substrate you should use until his condition is completely cleared up. Not only are they much cleaner than wood shaving to begin with, but they stay cleaner and maintain a cleaner environment because they dont harbor bacteria and mold as readily as wood shavings do. Further, they will not irritate the sores or burns or whatever they are (i wish i could be more helpful in IDing the issue) with dust and particulate like wood, and finally, they effectively show evidence of improvement or deterioration in the snakes condition because you can easily blood or puss, or hopefully the lack thereof.
Besides that, i highly reccomend you ditch the stick-on dial for humidity and/or temperature readings, they are horribly inaccurate - i know from hard-learned experience - a very popular option for budget minded herpers (like myself) is this digital thermometer/hydrometer form AcuRite, you can get them on amazon for around $15. I was shocked at how inaccurate my dial hydrometer was when i got the digital one, and because its indoor/outdoor (it has a probe for the second temp reading) you can track your warm side and your cool side with the one unit. Dang, i should be getting a commission from AcuRite for this post.