Months ago, there was a large, pimple-like lump on inner left cheek of buttocks. It lasted for days, was quite painful, and upon examination, it popped. What emerged was a bit of blood/pus, plus a hard, yellowish substance that was also smooth to a nearly polished state, and resembled a tiny egg or cocoon. It has not bothered me there since.

A few days ago, I came across the same thing, but this time in the natal cleft area. I looked up pilonidal cysts, but the difference is that what emerges from my skin is hard and solid. I am a young adult female (25), not/never been sexually active, and I have rather good hygiene.