How To Treat A Bruise On Top Of Calf Right Behind The Knee?

At the end of last summer I got what looked like a bruise on the top of my calf right behind my knee, but it didn't hurt and I couldn't remember doing anything that would give me a bruise. It has been there ever since and it still doesn't hurt, but today I noticed a thin white spot a few inches long in the same spot, partly over the bruise-looking thing. It's not hard, but you can feel that it is there.