Weird extra skin or lump under my butt cheek?

[Wolfiegee]

Alright, so I’m a 19 year old female, and this happened after sleeping with my boyfriend in a position where his prickly growing back hairs were able to rub against the back of my thigh, right under my butt. I noticed it became swollen under my butt so much that I could grab a handful, it felt like a whole new butt. That was about a month ago and the size of it has reduced a lot, I can only grab it with my fingers and it’s not as long, mainly starting closer to the inner thigh, and extends a little less than halfway of my thigh. Now it just looks like what I imagine it would look like if my thighs were chunky. It never hurts, except for when the skin first got irritated during sex, and right where there’s a “fold” between my butt and the thigh lump, there’s a little bit of what looks like a healing scar, it was a lot longer and redder in the beginning, and now it’s almost gone.

I just don’t know what it is and I’m hoping it will go away because it’s causes huge insecurity issues for me right as I started getting more confident from the gym. I’m a dancer as well and we wear shorts A LOT for costumes and when I wear shorts the scar part can be seen and it’s going to be summer soon and a