You have pigmented spots post acne. Follow this - 1) Use Frequent washes of face by Triclosan and zinc oxide soap (Acnil, Acnelak)
2) Topical treatment - morning times use AHA glow face wash then Sunscreen lotion (Suncote ,Sunkare, or Melaguard ). In the night use lightening creams i.e.Kojic acid with vit C or Combination of Hydroquinone, Tretinoin and Momentasome gives very good results.