I Fell 2 Days Ago Landed Right On My Knee

I fell 2 days ago landed right on my knee , bruised , pretty swollen , looks pretty bad , but can walk it hurts like hell but I can , it's so swollen , I feel heat generating from it , but now 2 days later it's shooting pain down my leg onto my foot , it feels like a foot cramp that won't go away , happened outa nowhere and it's killing me , what can I do