I Don't Know If I Got Bitten By Insect Or

I don't know if I got bitten by insect or what may have taken place, but on my left hand, top area I had two spots about one inch apart in a straight line.. Then after rubbing them daily after shower drying off, they turned into raw sore and now have scabbed over with a dark almost black scab...Over my 71 years of life I was told if you have a black spot or black scab, best have it looked at by doctor...