Hi mate, go to doctors as soon as possible. I didn’t and have just spent 4 days in hospital, had to have surgery on my knee to clean out a burst abscess. My knee is open to the bone as they don’t close up infected wounds. Having to attend out patients three times a week for dressing changes and is going to take months for it to heal up and then have to have physio to get movement back in knee. All because I got something in knee whilst shooting, and ignored it for a week. Good luck, get it seen to.