Hello, Welcome to healthcare magic. Your skin tone is determined at the time of your birth itself and it is decided by the concentration of melanocytes and circulation. But most of the people will acquire more pigmentation as age increases, we call it facultative pigmentation. Lot of factors determine it, most important being sunlight, others include dust, pollution, smoking, less hydration, intrinsic ageing and free radical damage, stress etc. Treatments should be to bring your pigmented skin back to your normal skin tone and make the skin tone even all over the face. I would recommend you to use a face wash twice a day ideally a one containing glycolic acid as it helps in exfoliation and to even out the skin tone. The most important product will be a sunscreen. Half an hour before going out apply a sunscreen and reapply it every three to four hours. At night you may apply a lightening cream containing kojic acid ( eg: Kojivit gel) over the face before going to sleep. You may consult a dermatologist practicing cosmetology for few sittings of chemical peels for faster improvement. Hope I have answered your query. Take care.