After 6 Weeks In A Cast On My Forearm, A

After 6 weeks in a cast on my forearm, a brown scabby, patch developed where a smaller dry spot was. The original spot about 1/8 inch now is size of a pencil eraser. The new spot is flat but raised and asymmetrical in shape. 65 yrs. Old and I have a physical next month. This is the only spot on my body. Should I be concerned?