It’s quite possible that it’s what’s known as sore hocks. It’s usually caused by your rabbit resting/running on surfaces that can be hard or abrasive on them. Wire mesh bottomed cages are most common causes, but hard plastic bottomed or wood cages can cause it too, some bunnies even get sore hocks from carpet. Urine scalding on the feet can also cause sore hocks, or even overgrown nails. You can try to prevent it developing further by offering multiple different surfaces for your rabbit to sit on, such as soft fleece, or a foam mat etc. If it seems red, inflamed, and/or sore then you may need to get something to apply for it, but I’m honestly not sure what the appropriate thing to apply is, may be best to check with your vet.

Make sure you change the litter tray frequently as damp litter can make it difficult to get rid of the problem if your rabbit spends a lot of time in the tray (which most tend to)

Pink, hard callouses are fine and normal in a lot of bunnies. Just monitor them as part of your weekly grooming routine. If they start to become cracked/open, red, inflammed or bleeding, you will need to treat them and improve her flooring.

Hard to tell from a pic but looks pretty normal. Maybe a bit on the red side. If your bun won’t chew them, I highly recommend memory foam bath mats. They did wonders for Olivia’s sore hocks.