My previous rabbit also had something like that on his front foot-it was red and irritated, bald and crusty, and when i did the stupid thing of squeezing one of the weird whiter spots, goo came out, as if it were a pimple. It came out from both sides, creating a tunnel-y crater of sorts. We didn't go to the vet though, as it was just added to the pile of ailments he had, but definetly something you should do to get it checked and treated properly.
Meanwhile you could clean and check her enclosure, maybe swap flooring depending on what you have, and use neosporin as mariam+theo suggested.
May she heal well!