I Recently Fell To The Left Side On My Bicycle

I recently fell to the left side on my bicycle (race bike). Beside a couple other injuries, I also got a large bruise on the inside of my right knee. (I am a woman in 50s and my knees have always been a little chunky anyway, but it did swell soon and get hard in the center 2-3 inches, right after.
Problem is, the main area (about 3" diameter) is hard and sometimes itchy, and it has been since July 15, when the accident happened.
How do I get the taught, hard area to gt softer?