Should I be concerned?

RoseEva • US Navy Sailor
I've had a painful bump in the same spot for awhile now. Today after my shower I decided to finally figure out how to get rid of it and its a purple/ black colored solid lump right between my leg and the lips. I've read online it could be caused my my underwear lining being too tight. 
Should i be concerned of the lump? Or does anyone know how i can treat it?