Sorry to hear about your kitty's problems.
We have two cats and we've noticed that one of them gets infections in wounds much easier than the other one. We really have to make sure to clean even the smallest of wounds on that cat or we'll be off to the vet again. Two years in a row we missed an infected wound and the poor guy wound up spending several days at the vet having his wounds treated. The last time this happen we didn't notice the problem right away. When we did notice something we thought he had a few little scratches around his ear and eye that got infected. When we took him to the vet and the vet shaved the area it looked like something tried to bite his head off.
It sounds like you are on top of the situation so I'm sure she'll get better soon.