Roxy (my 8.5 year old pitbull) has a bump on her butt, literally beside the tail. She's had it for a couple of years now and the vet said it should be fine aslong as it doesn't cause any discomfort or pain. The bump usually grows in size during specific seasons, and reduces in other seasons.
It is leaking some plasma/blood now whenever she sits down, and she does lick it from time to time. Does anybody have any recommendations on what I can do? I'm pretty sure if I goto the vet they'll tell me the same thing :[
Here's a picture of her

