Thank you for your quesiton, I'm Dr. Dan and I'll try to help you.
I'm sorry your python has been burned. There are a couple of steps you need to take.
First you need to remove any heat rocks or under tank heaters and provide heat with lighted heating (heat bulb or heat lamp), something he cannot contact.
The second thing you need to do is remove any bedding that could get stuck in the burn (wood, sand, rocks, dirt, etc.)
The third thing you need to do is to apply a burn cream (over the counter human) to the wound daily to protect it until you can take step 4.
Step 4 is you must see a vet for systemic antibiotics or possibly surgery! The foul smelling tissue needs to be treated more than topically because of a snakes slow metabolism. Usually oral or injectable antibiotics. If there is tissue that is completely dead it will harbor infeciton from the antibiotics and needs to be manually (surgically) removed before the antibiotics work. If you take care of this before he stops eating or becomes lethargic he can be healed, but taking the wait and see approach or avoiding the vet likely will end up with a dead snake :(. I hope this helps, if not please feel free to ask more questions, if it did, please leave a rating. Dr. Dan