What Causes Painful Cut At The Vaginal Opening?

About 2 months ago i found a small painful cut at the opening of my vagina, i was already in the doctor for a subcutaneous cyst on my vulva the week before and started experiencing some irritation around my anus which they originally said was hemorrhoids but swabbed if for herpes to be safe. Then the cut appeared and they swabbed it for herpes again. Both swabs came out negative. my partner and i went and got blood tested for hsv 2 and we were both negative but it did show i had hsv 1. I started taking acyclovir to be safe but after 20 days of taking 3 pills a day nothing had changed. they treated my for a yeast infection and there was some relief but the cut was still there and painful. I have been to a number of doctors but no one knows whats going on as the cut is very slight but really painful and has lasted a long time without any relief. I went to a doctor last week who gave me a round of antibiotics to try but nothing seems to have made the cut more painful and yesterday i found another one. I have no idea that this is as it has been swabbed for herpes many times as well as strep b and yeast and nothing seems to be positive. please help!