Poor you and Miley. Regarding the hole in her leg. I've seen this before when a cat have been in a fight with another cat. The bite or claw mark heals over so you don't notice it at the time but then festers and pops a week later, removing fur and leaving the nasty hole that you describe.

Sometimes we would notice the swelling from the festering and applied hot compresses to them to get all of the infection out and they've healed up just fine. Only once have I had one that wasn't healing so good (on Sids tail), and I brought him into the vet for some antibiotics. Even then the vet said that it was healing as it should and the antibiotics were merely a precaution.