I opened my car door rather briskly, thinking my legs were clear of it. The bottom pointed edge of the door collided with the inside of my left knee. The site is bruised, sore and somewhat swollen. There must be some fluid, i think, because may ankle and foot are quite swollen. hurts worse when I have sat for a while and get up. Then the knee is really sore and stiff, making it embarrassingly difficult to stand up straight and walk without a very obvious painful limp. Also, Is there a possibility of a blood clot? Thank you.