Knee fluid... what could be wrong?

i had a motorcycle accident about 2 weeks ago... i hit my knee no brokend bones or damage mucles... so my doctor put some stiches .... but the cut didnt close all the way... so i still have a little open skin but there is some kind of fluid coming out of my knee... i been taking antibitics and i am sure that is not pus... this is some kind of yellow fluid and its really thin.. doest have smell.. what do u think it may be? i am freaking out!!