doctored with foot ulcer since feb 14, but still not healed. Yesterday the foot doctor said he was puzzled as to why it is not healing. Some spots heal then they come back again so he sending Dad to a dermatologist to get a biopsy. From what I have read about foot sores, a biopsy probably should've been done in the beginning... Please help. Dr. says no signs of gangrene or close to the bone, but it sure looks raw to me.