Firstly its important to assess the cause of pigmentation. You'll need skin lightening creams for a specified duration to reduce the marks , and this could also be dealt with chemical peeling. Also you must use a sunscreen to prevent darkening of the spots. For actual scars, creams may not work n you may need procedures like microneedling, microneedling rf, fractional lasers, prp or a combination of these. . Hope this helps. Warm regards.