Nodule/lump On The Upper Right Side Of My Vagina

A week and a half ago, I was showering and noticed that I have a nodule/lump on the upper right side of my vagina, on the labia majora [the soft, fleshy, pink area, not my actual skin, though it is closer to my outer skin than the inside of my vagina - when I stand up it's on the very outer edge of the lip, not entirely inside].

Of course, I freaked. I have been sexually active for several years. I have been consistent with using condoms, but several months ago when I was casually dating someone and we had sex, the condom broke, slid off inside me and naturally we had 'skin to skin' contact. So I am scared of HPV, I was scared of herpes too but I was relieved when I passed the 2 1/2 week incubation time for herpes and nothing showed up. He said he was tested every 6 months and he was an honest, if not blunt person and had no reason to lie. But I am worried. 

To describe the bump: it's more under the skin than above it, if that makes sense. It blends in with the surrounding skin and it feels like a semi-hard lump that moves around a bit when I touch it. It's almost painless and it doesn't itch. When I pull back the surrounding skin [to expose where the bump actually is], it looks like a dark white color. I've done a few compresses and it's gotten slightly smaller, but otherwise hasn't changed. It doesn't look like any genital warts I've looked up online...in fact, it almost looks like a cyst but it doesn't have a head right now. I was shaving a lot, with not a very sharp razor either, often for the 2 1/2 months preceding the cyst. I have also been on 2 new birth controls recently, and I have been getting cysts on my face, so I wonder if you can get them on your vagina, too [?].