Hi, I can understand your concern for pimples marks on your face. Acne or pimples are youth related problem and is not a disease per say. A gel containing clindamycin phosphate 1.2% w/w and tretinoin gel can be very helpful to you for long term in case of acne. The only precaution you should follow is to apply the cream in very thin layer and that too over affected area only. If I were your dermatologist then I would have suggested you to use azelaic acid cream or Kojic acid cream or glycolic acid cream or licorice extract or arbutine creams at night time in guidance of dermatologist. The most important part is to use a sunscreen regularly in open environment and on exposure to sun. Take a proper guidance and follow up with a good dermatologist so that all the problem can be dealt best for future time.