Just saw this thread... the black discoloration does look like frostbite damage, at least from the photos. Especially if it's sloughing off with pink, healthy skin underneath. It's sort of a strange place for her to get it (usually the toes or pad of the foot gets it first), but is it possible it is frostbite? I don't know where you live. If you live in a climate where frostbite was unlikely, I'm not sure. The blackened scales is surely not bumblefoot but it's not normal either.
I agree, if you started penicillin, I'd recommend following the full course. Doing only a partial antibiotic treatment can actually make things worse.
I agree, if you started penicillin, I'd recommend following the full course. Doing only a partial antibiotic treatment can actually make things worse.