Rapidly growing discolorations

On my upper thighs and on the area between my pubic and abdominal regions there are a dozen or so rapidly growing discolorations. I hesitate to call them moles, because they are growing too fast and are too flat. They are a few shades darker than my natural skin tone in that area, and they flake a bit when scratched. The blemish that I could best describe them looking like (aside from the flaking) are birthmarks. In the past month one of them has grown from the size of the head of a pencil eraser to the size of a nickel. More are showing up every week. There is a history of both breast and prostate cancer in my family, but these discolorations don't really have any of the signs of melanoma. I'm abstinent, so I'm sure that it's not STD related. The fact that they're growing so fast is what scares me the most. I don't have health insurance, so I've hesitated to go to a doctor. I'm really getting worried now though, so if anyone could tell me what's going on ASAP, I'd really appreciate it.