A couple days ago I noticed small brown spots between the back of my thumb and my index finger. I thought it was dirty at first but it wouldn't wash out. The next day another brown bruised like spot appeared but a little bit down from my index finger nail. It doesn't hurt or anything so should I be worried? The brown spots are only on my right hand. At first I thought it was age spots but I'm only 14 so how could that be possible?