Hi, I can understand your concern for the problem of pimple marks in cheeks. In pimple marks there is overactivity of melanocytes at epidermal region. Melanocytes are the color producing cells of skin which causes superficial and deep pigmentation which may appear as pigmentation. Lightening agents such as Kojic acid or azelaic acid or Hydroquinone cream application which you can use under dermatological guidance. The most important part in treatment is by sun protection by all measures. Eat healthy diet containing lot of Vitamin A and Vitamin C. Do not try applying over the counter products as these can further aggravate the situation. Protect yourself form direct sunlight. Use a good sunscreen on exposed area for 2-3 times and drink plenty of liquids everyday. All the best.