Thanks all for the replies. I still don't think it's necessarily a cyst as it's so deep under the skin and fatty tissue, and it seems like it's a little too far back to be a bartholin's cyst. (Perhaps I should have been a grown-up and mentioned that it's location is more like to the side of the perineum, about where the inner thigh meets the groin).

That said, I'll try the hot packs and see my doctor if it doesn't begin reducing in size and/or (heavens forbid!) worsens.

Thanks again!

I'll try to have my next post be something with a little more decorum.