Suggest Treatment For Knee Swelling And Bruising Sustained While Playing

The other day i injured my knee from volleyball. i continuously kept diving and when i did so my knee slammed on the floor. I started crying because of the pain that i was recieving. I looked at my knee and its swollen to the sides and i have bruises all over. is this just badly bruised or what could the diagnosis be? also, what would the treatment be? thank you