True, Joe, but many of us have shared similar experiences so it doesn't hurt to hear what those people have to say. Always keeping in mind that what they say is just an opinion like everything else you read on here and not a professional diagnosis.
That said - are you a man? Cuz if it ain't gushing blood and you can still function you don't need no stinking doctor.
I've felt that "bruise" below the knee cap myself. It went away. I've also had a pop in my left knee for 20 years everytime I flex it and never had knee surgery. It sounds to me (me no doctor or anything of the sort - just to be clear) like you just tweaked it and bruised or sprained something.
My advice is - don't jump when the boat is turning!