I think we're through with the vet! I took her in and he looked it over carefully. He squeezed and picked at it. She was such a good girl. He even remarked about how good she was being. He took her temperature, and it was normal. No real pus came out. The lump is about the size of a quarter or maybe slightly bigger. He called it a capsule from the abscess. He said that it should go away on its own in about 6 weeks but to just keep an eye on it to make sure no more infection looks like it is in there.