The treatment of pigmentation depends upon the type of pigmentation you are having.
If it is mild, it can be treated with creams alone
If it is severe or deep, creams peeling sessions or LASERSmight be required
Nevertheless to start with
Use a Glycolic or salicylic acid
based face wash
Apply sunscreen regularly even if indoors
Take oral antioxidant and vitamin c
Apply Kojic acid
arbutin based cream in morning and Glycolic acid
or triple combination cream like melacare in night. Do not use melacare for more than a month. If redness or irritation occurs stop using the cream.
Hope that solves your query. Take care.