this case with Fletcher reminds me of an issue I had with a green tree python. She bit the screen of her cage and broke some teeth. I monitored her for a while and they were growing back beautifully then all of a sudden she developed a brown spot on her gums and the teeth fell out again. The vet said it was gingivitis. lol. I treated her with an antibiotic ointment till it was gone. Then it came back. Treated it again. Came back again. Finally her immune system beat it. That might just be whats going on with fletcher.