I have oily skin so i always use powder to set my make up. My procedure is like this: use a mousse foundation, apply concealer on areas required n pat on compact powder. But even when i use the exact tone of concealer or one shade lighter, the area turn darker after i pat on powder, making the flaw even more conspicious. What did i do wrong? any recommendations? I have fair skin with a few dented acne scars on cheek.

once make-up sets is can change tones. oily skin is the worst for this. the oils set in the makeup and naturally change the color. they have concealers for oily skin. i would go to a professional make up counter ...like not walgreens...mayeb clinique prescriptives or estee lauder and see what they recommend

Is your concealer a shade lighter then your skin tone like its supposed to be? If not that could be the reason.