What Do You Think Would Be The Cause Of The

What do you think would be the cause of the lower left outer vaginal lip being swollen? Feels like a internal bump as if you hit your head and get a bump. Absolutely no pain or discomfort, simply a concerning bump. No irritation or discolouration either. Could this possibly be caused by rough sex? Will go see my doctor but have to wait a week because I started my period.