My pug has a bump around her rectum and now it is has pus coming out of it. What could it be?

This is gross but they have a gland that has to be emptied out there.You can take your dog to a vet or even a dog groomer,or maybe the vet can tell you how to do it.You have to push it a certain way but I dont know how to do that.Smaller dogs have this problem.You should probably just take her to the vet,just to make sure.Good Luck!