I have a hard-ish lump near the opening of my vagina, really on my butt cheek and I ve had it for a while and it goes away sometimes. I m prone to getting acne down in my genitals and it hurts a bit when I push on it. You can t really see the lump because while it s about the size of a dime, maybe a little bigger, it s very flat, which leads me to believe that it s right under the skin. DO you know what it is?