Fell hard on my butt 8 months ago and now have a huge dent that’s not healing. What are my options for fixing it? (Photo)

i fell down the stairs while moving a very heavy box and landed right on my butt cheek. it left a massive eggplant sized and colored bruise and as that started to fade and the swelling went down, i was left with a massive dent in my butt cheek. it doesn’t appear to be improving and i’m delusionally wondering if it ever will on its own. seeming that this is likely not the case, what are my options for filling that dent in a way that is minimally invasive (i watched my mom heal from a bbl and it detered me very much from doing extensive body surgery, i couldn’t handle that level of physical trauma) and is permanent. also why did this happen? my guess is some sort of necrosis of the fat?