Any doctors in the house? Or at least someone who can pretend to be?

I fell off the sidewalk like 3 days ago and cut my knee open,apparently it's an 'abrasion' or something.. but yeah,it's not healing,its still all wet and gooey and gross,and it changes from red,green and yellow occasionally. I'm not that worried cause it doesn't hurt, I just want it to heal,anyone know what to do?