Two days ago I noticed a little brown spot on my left arm on the upper side near my elbow. It looked like a mole and I thought it was a scab because it was so small (the size of a pinhead). Today it is a light tan color and the brown has disappeared. It is still really small...About half the size of a pencil eraser...And it will not come off. I tried scratching it like a scab to see if it was nothing serious, but it looks strange. Does cancer grow that fast? Double the size in two days. Does it just sound like a little sore? I'll update it. Keeping an eye on it...Any opinions would be nice.