Hi there...I can understand your concern. It would have been better if you had posted a photo of the pigmentation. At your age, you are problem suffering from melasma. You should first understand that it is very difficult to completely cure melasma. It's etiology is related to hormonal variation. Also it can increase on exposure to sunlight. So using a sunscreen is must. Consult a dermatologist so that they can diagnose correctly and treat accordingly.