How To Get Rid Of The Bump Formed On The Buttocks Several Years Ago?

Several years ago, I fell off my bunk bed in college and landed on my rear end. I landed on a shoe and after a while a bump formed on my butt. It still is there. Is it something I need to get checked out, and will it go away? It doesn't hurt, it's not colored strangely, but it's a little big (maybe 2 inches in diameter). I'm 25 and I fell when I was about 22.