A ball pythons head and mouth are the most sensitive areas of their body's. As such the least little thing will cause an abscess/infection, You feed F/T but that doesn't mean that in the eating process some slight damage didn't happen. A simple scratch inside the mouth even from a dead rodent's tooth or toe nail is more that enough to allow bacteria to settle in and reek havoc. I've seen this only twice in my years of keeping and breeding, one time the abscess ruptured the snake healed and all was fine. The second time I spent 2 months treating with a regiment of alternating Baytril and Forataz in the end nothing was able to fully heal the animal and we lost it.
My suggesting would be this..Feed smaller meals and about half as often the less stress and work damaged area is having to do to heal the better. Second if you haven't already get injectable antibiotics, snakes metabolisms are so slow that oral treatments almost never work for more serious issues, that coupled with the fact that the stress involved in giving them is just as bad to the animal as the injury. Third, your snake is off limits to handling, videos, pictures, show and tell or even the morning stroll while you're having your coffee. Your snake needs to focus all it's energy on healing. Lastly bump up your temps just a few degrees over your normal keeping temps, as cold blooded critters snakes use the extra warmth to help speed things like digestion and antibody product up, Heat = Bio - fuel
Please let us know how it turns out.