What Causes Dark Mole With Black Head Next To Vagina?

I had a PAP test today and my doctor noticed what looks like a mole next to my vagina. It was darker than my skin, that's why he thought it was a mole. However, when I got home, I noticed it was "loose" from my skin and it came right off. Attached to the black head was a white seed-looking thing. What is this??