Pain meds?

I recently torn my ACL and Meniscus in my left knee. My dr gave me percocet 5mg and it says "take 1 or 2 ever 4-6 hours". Well, I have been doing that, but it is not helping at all. I don't want to ask for something stronger because I'm afraid that he will think I am just trying to get high or something. What do you suggest saying to him that will make him feel that it is actually the pain making me ask and not drug seeking as i've heard it called? Is there a suggestion for the type of medication I should ask for?