In the groin is a typical place for a skin tag. Is it soft and moveable? How large is it?
A skin tag is benign> I once had one turn black so I saw the doctor. He said it had "died" and would fall off and sure enough it did. But it was the right thing to do to see him as it had changed colour. Keep an eye on your mole and if it changes then please see a doctor,
In the meantime check out skin tags.