Oscar fish has grayish patches on him.?

I have an oscar, his tank is clean (i clean it every other week) and i put ich/parasite treatment in his tank every so often. he's had some grayish patches in front of his fins for a while now. The treatment i put in the water didn't do anything. could they be scars? sometimes when he wants my attention he zooms around the tank and plows into the gravel at the bottom. im just wondering if he could have scared himself on the gravel.