I had it for a couple of years. Small spots. Tried to dig it out and made it worse. Tried everything. Creams, Duct tape, capping with Super Glue digging to the root. Nothing worked.
While learning to Kite Board on the desert lakes I had several days walking bear foot on the sandy beach in hot sand. A few times it was burning hot in the middle of the day. I notice weeks late my feet where looking brand new. Nothing but smooth skin.
It had to have been the Burning Sand on bear feet.