Okay, here's the story: my parents have a bed with a very prominent bed end; it's hard wood and comes out from the mattress a few inches. Earlier tonight, after sitting on their bed talking to my mother, I stood up and whacked my upper leg on the bed end. It's happened before - at some point or another, everyone in my house has whacked some part of their body on the damn hard wood bed end, but it caused excruciating pain at the time. This happened several hours ago. As I was about to go to bed, I looked down...and found a somewhat unexpected sight. See, last time this happened, all I got was a small bruise. This time, however, it's not just bruised. In the "center" of the wound, it's swollen, a little red, and very, very sore to the touch, and a little hot as well. There's an outer, very bruised ring around this middle bit. The inner part (where I would have hit it) is about 3cm in diameter, the outer ring goes out about 1-2cm. Not small, very bruised and blotchy.

My question is, could I have ruptured a tendon or torn a muscle? As I said, I've got my leg on the bed before, but this time it's different.