Update: Took Peanut to the vet. It is not Bumble foot. The bottom of the foot is fine, it's just that the foot overall has lost hair and is red. They ruled out mites and other parasites. They said that it could possibly be ringworm so have taken a culture and provided topical ointment for now. We go back in 2 weeks for follow-up.
At home we have moved her to separate cage and will be taking extra precaution.