It's too early. Salty water may have a healing effect, but the water will also re-open the wound and slow down the whole process. Haha, I don't knee paddle, but how do you think people get up on their feet on the surfboard? You pull up one knee (while it slightly scrapes over the board) and then you pull the other one forward. Both knees might get in contact with the surface of the board which is usually a sharp-edged mixed of wax and sand. It's like sandpaper and I really don't want to pass my open knee over sandpaper right now - lol.
I'll get that knee fixed and then I'll be back in the water soon :-)