I have one on my left arm and its the size of a nipple (ew), and i've had it since i was a kid. I have the same kind on my shoulder, on my the right side of chest and under the left arm. Its the same color as my skin and its all roughly the same size. It doesnt hurt, and i once tried to cut it off with a knife, only it was like cutting a part of my skin really.

It looks horrible and there's a small one of it on my leg now and im scared it might grow or something. Know what it is?