Any problem I ever had with my Oscars was cured with Salt and a jump up in Temperature. Usually cleared up very fast. Never had to use Meds (Melafix, etc..).
do you have sand for substrate? ... my oscar often looked like that when i had sand in my tank .. they like to stir the sand up and would coat themselfs with it ..which made it look like they where shedding? ... i took the sand out ...havent had the problem since ....... your pics are kinda blurry ..cant really tell if thats the situation your having ..
could be hith just do 50%water change check your water readings ammonia and nitrites should always be at 0 and nitates should be below 40 but less than 20 is better. if you keep your water in good condition the prob should clear