So as I mentioned earlier, I'm in the same boat, and here's my experience. I fell a few days before Christmas Superman style onto the concrete sidewalk. The first 2.5 weeks, the ribs were the main problem. Almost impossible to run. I had also hit my knee, but didn't notice too many problems with it during those few weeks on the few runs I did. I don't know if that's because it was overshadowed by the rib pain or if it took a few weeks for the knee pain to surface. Once the ribs were better, I realized the knee was much worse than I thought. In hindsight, I wish I had done more for the knee in those first few weeks.
When I first fell, I immediately got a small goose egg about the size of a marble on the top lateral corner of my knee. It's still there today, but not as big. When I noticed the knee was worse a few weeks later, I was feeling the pain about an inch below that bump on the outside of the kneecap.
So for the past month, I've done the whole take a week off, try to run a few days, take more time off, try again deal. I can get it feeling to almost 100% with time off. Been working on rolling out the quads too. For a while, going down steps was bad, but not as much now. But after a few days of running again, it gradually starts to return. For me anyway, it doesn't seem like time off is the answer, unless it's a whole month or something. And I'm not willing to do that if it's just going to start back up again within a few days of running.
Right now I'm under the assumption that it's either a bone bruise, tendonitis from compensation, or possibly a tracking issue and the outside of the kneecap is rubbing on the cartilage. I've had some adjustments, and I've been told everything seems to be in place. I've had x-rays (which were normal), but no MRI. That might be the next step. At this point, the only thing I haven't really tried is just jumping back into full training and see what happens. If it doesn't get much worse, then it's probably just a bone bruise that's going to take time to heal completely. That's kind of where I'm at right now. It's very aggravating because it will feel great with a few days off, so I'll feel like I'm ready to go and wasting time just sitting around. But as soon as I start back...same old story.
And I'm still icing every day. No heat. Did do a few epsom salt baths in those first few weeks, but none now. Been using arnica gel also. And doing a little KT tape when I do run.