help ! Post Acne Mark

As a teenager, there’s a lot of problems to begin with. Combat with stress and hormones, it becomes clear that in one moment my face was full of pimples. After successfully extracted and drinking chlorophyll which does help combat my acne and my acne only appear during my period only. I left with a face full of post acne hyperpigmentation. I didn’t know what to do and recently I purchase somebymi yuja niacin serum which I saw online that it’s good for lighten acne scars. But it seem there’s still those hyperpigmentation on my face. What should I do ?