What Causes An Abscess On The Labia?

I just was told I may have herpes, scared me to death, brought me to tears let alone there is no reason for it... anyway, after doing a bit of research on my own when I got home my symptoms don't appear to be herpes related but more like a labia abcess. I have had fast swelling with much pain (unable to walk, sit etc) w/out pain, took sitz baths, and opened it myself to remove the pus after a couple of days. In the past when this occured a hard knot was left but no pain. This time most swelling is gone, still tender and still draining. The gyn said she didn't feel anything but lesions...I am 53 yrs old and this began about 2 years ago, with minor incidents and now this is the 3rd larger one..herpes test will be back in two weeks, but I am calmer now as I don't have the symptoms of herpes from what I have read... any guesses on your end?