band-aids. my knees is like that, skinned it...long story. anyway, clean it bad with hydrogen peroxide then put neosporin and a band-aid on it, put a fresh band-aid on every morning (and neosporin) and it'll get better before you know it
thats pus. its infection, so you want that crap to overflow out. don't try to stop it and instead wash it so it won't get infected again.
next when its all gone put neosporin on it or something.