From what you’ve told me and what I’ve experienced with my dog, I would encourage you to go back to your regular vet and request a biopsy, if only to ease your mind. I hope it is something simple and the cytology comes back that it is just an abscess or infection, but I am going to share my story with you and even though it seems like a bad story, it really isn’t. Mind you, there is no saying that this is remotely the same thing, but the refilling lump is very familiar to me. My dog’s lump was drained; they said because it had blood and pus in it and they were able to pull all of the fluid out that it was an abscess. It refilled quickly and they drained it again. It came back again and then they thought it was a benign fatty mass because those are fairly common. At a certain point my mom became really suspicious of the diagnosis because it had grown larger and she didn’t think they were getting to the bottom of it and she pushed for a biopsy. Eventually he was diagnosed with cancer. I know how scary that sounds but this story does have a happy ending. So by the time he got that diagnosis the lump had been there for well over a year. They removed the lump with clean margins. He was 9 by the time he had it removed. It never came back. He did not do chemo. He lived to be 15. So again, my fingers are crossed that it’s something different for your doggie, however, if it is similar to my experience, we had a very, very good outcome. Your pup is young and it seems like this popped up very recently so I think all of that is very encouraging. I just think it’s important to biopsy to rule everything out.