Should I be worried about swollen feet after a knee injury?

about 3 weeks ago I fell down some steps and had to get 23 stitches in my kneecap. I had to wear an immobilization brace for 7 days. This week I got my stitches removed and my feet have started to swell during the day and returning to normal at night. I'm not sure if this is normal or something I should be scared about. I'm trying to keep my foot elevated as much as I can, but I work at a desk all day. Any info would be appreciated!