Hi.. Acne and skin discoloration both need time to heal.. You can use skin lightening products available in the market. Choose the best one which is suitable for you. I use garnier products which I find useful.. If none of these products are effective and you are cosmetically worried of discolouration, you can go ahead with dermaabrasion. A minor surgical method of correcting it.. You can take a second opinion with a dermatologist if interested for better skin care products..