I had a poodle who had this. We where at my sisters getting ready for her wedding. I kept a diaper on her at night to make sure she didn't have an accident at my sisters. Well when I took the diaper off it was full of pus. I was in a complete panic. It was my sisters wedding day and I had to do everyones hair. My husband and dad took her to the vet where they gave her a shot and antibiotics. They said to get her spayed as soon as we got home. My vet said it was much better that it drained out or the outcome could have been much worse. She went through everything really well. I would get Megan spayed if I where you. I hope everything goes well.
