Beulah has been chewing on her tail (the part where her tail meets her back), and now it has a big sore on it. I don't know why she is doing this, she doesn't have any fleas or anything. She will just sit there and chew on it. It looks really bad and painful. Everytime I see her chewing on it, I make her stop. Can the vet do anything for that? Give some ointment or something to put on it. I mean, it can't be good right?