Well having read that I think I've got away very lightly.
My doc (who is also a close friend with whom I've done lots of sports stuff, and who has also tended most of my footie injuries) says no breaks for me or serious damage to cruciate ligament, just massive patellar bursitis and bruising and some tear damage to thigh muscles and ligaments around knee. He drew off half litre

of watery looking blood from around the knee to reduce the swelling and what a difference it has made! 75% of pain disappeared instantly and I can bend my knee again, enough to get back on a bike!
Now some physio to strengthen and mobilise knee and make sure no problems with scar tissue in muscle, tendons and ligaments. What was shocking was the effect, in only 17 days, that limping, guarding, and minimising use of the leg has had on the quad muscle! Age must accelerate loss of muscle mass and tone. I've had many leg injuries over the years but never lost muscle so fast before!
As I say, I've got away lightly. Your injury sounds like the thing I was most worried about developing and why I was very happy to have the fluid drawn off so the risk of infection was (hopefully) removed.
Make sure you eat lots of good veg and fruit in your diet, and drink water to help your immune system to do its job properly. I would recommend getting your doc to refer you for physio as soon as the infection and pain allows.
Hopefully the most pessimistic prognosis will not prove to be the case and you'll be back up and riding again soon.
Best regards,
NJ