Without the foot being washed it is kind of hard to tell for sure. But it appears as if it could be Bumblefoot. If you wash her foot and see a round area on the pad, almost like a scab, then it is likely Bumblefoot. You can see if the scab will loosen around the edges. If it is sealed off then just squeezing may not show you anything. If it is Bumblefoot it will only get worse, so you will need to treat it.