She has a Granuloma ,basically a wound or injury to the foot with proud flesh poking through , so you can ask your vet how to treat , for me i would put copper sulphate powder or iodine and sugar mixed to a paste on the wound and then bandage , give a painkiller and check / repeat every few days . Do not trim any of the hoof for now as it will act as a cushion but when she's healed then a trim would be good to stop dirt /stones getting in the holes