Hi, I can understand your concern for marks after acne. These marks are activity of melanocytes in the superficial epidermal layer of skin or due to atrophy of the skin leading to scarring. Lightening agents such as Kojic acid or azelaic acid cream application which you can use under dermatological guidance. So considering the above facts you can apply these cream but only under dermatological supervision. The most important part in treatment is by sun protection by all measures. Take a proper guidance and follow up with a good dermatologist so that all the problem of pigmentation can be dealt best for future time. Eat healthy diet containing lot of Vitamin A and Vitamin C. Take care