Just recently I had a 1/2 inch diameter black spot to come on the end of my big toe. There is no pain, no raised area, just black. First I thought it may be black dye from the inside of my shoe, but I used acetone to see if it would come off and it didn't. It's been there two weeks now and it still hasn't come off. I would never know it was there if I didn't look. What's the answer? Don't look? Not really it must have been caused by something. It's never happened before.