Hi, I ve recently noticed what seemed like a bruise at very bottom of my back, top of my butt cheek (sorry to sound vulgar). Seemed like nothing, until it started getting darker. Now it is an indentation on my skin and is blue. It doesn t hurt, it s not sore or anything. Just ugly. I m getting concerned, I ve never seen anything like this before and it doesn t seem to be going away. Any info? Thanks!