Cut knees can hardly walk please help?

fell over after a good night out lol didnt realise til this morning been agony can hardly walk stairs almost impossible, cleaned it tho i dont know if theres any grit in it, on 1 side theres a big patch wiv no skin and its oozing stuff lol even lying here it hurts if i bend my legs i nearly scream help! how long will it be till its better? any tips? x x