How to remove a hard patch of skin on left ankle and causes?

WHAT IS IT? The question is, is it nothing or is it something? Skin problems are really visual problems. Is it just callused skin, or something that needs a biopsy? Is the border choppy and irregular, color changes, size larger than head of pencil eraser, itch, drainage. Only by a doctor's exam can it be determined what to do next. Sincerely, Dr. Latva.
Usually trauma. Calluses form at sites of skin trauma and usually due to footwear if on the ankle. Changing shoes or adding a layer of protection/cushion at the site may help. Frequent moisturizing may help too.