7 month old bruises?

Last December in a freak accident I fell off the curb and onto my left knee from the sidewalk. I had a great deal of pain in my knee (I fell so hard my backpack flew up over my head!)-- I didn't know if I could walk -- but I could, and most of the pain went away in a couple of weeks. However, there are several small "bruises" (brownish colored) which I sustained which haven't gone away (my skin was slightly skinned, but I was wearing jeans at the time and there was no real break in the skin). Could this be an indicator of some sort of internal damage or what? (I've gotten plenty of bruises since then that have gone away in a normal period of time.) Thanks for your time.