Could it be an abcess tooth???? Is is swollen a little bit?
Veterinary Medicine Singapore Dr Sing: 23. Moral ethics and economic reality in carnaissal tooth abscess
Dudley had one and I thought it was an insect bit that wouldn't heal, althought he never displayed any signs of oral pain.....He was on antibotics for 10 days and it scabed over then the "puss" came back again and it will just repeat the same pattern until you get the tooth removed....GOOD LUCK