Repeatedly fell on my knee during a run. right knee is slightly swollen after 6 days but swelling seems to slightly be going down. stabbing pain in knees when i kneel. will this heal over time?

This is hard to predict. We don't have access to any information about your past and current health, prior injuries, findings of a direct knee exam, x-rays or MRI findings. If it bothers you let your doc look it over. S/he can decide if it is minor or needs tests to decide what if anything is needed.

I am curious why one would need to fall on their knees repetitively . You bruised the joint. X-rays needed to look for possible patella fracture. If the later very important for immediate care to prevent healing in a mal position and early arthritis.