About two weeks ago, I noticed a small dog on my hand, about the size of a pinhead. It is dark brown (almost black) and raised. I did the ABCDEs to check if it might be melanoma, and found that it is asymmetrical and has an irregular border. It hasn't grown or moved, but I am still worried. It is on the underside of my hand, right where my pinky meets my palm. Should I be worried about this?