Stitches in the Knee, Need Advice.?

yesterday,
during p.e. my class had to run a mile for the presidential fitness contest or whatever it is
which means that we were being timed & our teacher said that we could not walk or stop
while i was running i fell on these square thingies,
i dunno what they are call but they look something like this
http://i721.photobucket0o0com/albums/ww212…
the brown is made out of concrete and the green is grass/dirt
when i was running with my friends my shoe got caught on one of the squares and i fell and hit my knee on the concrete
it was painful >_<
i went to the ER and the physician said that a whole chunk of skin came off (yes its disgusting) & she had to sow my skin together so it could grow back properly
i got 5 stitches and this is the 1st time for me and neither of my parents have gotten stitches
she gave me instructions on how to take care of it and i know that i cant participate in any physical activities or bend my knee until the stitches get removed which is in 10 days

im just wondering if you have any advice that would be helpful for me
i would really appreciate it (: