To prevent further darkening, apply a broad-spectrum sunscreen with SPF 50 or higher daily, reapplying every two hours while working outdoors. Look for sunscreens containing zinc oxide or titanium dioxide. To treat existing spots, use topical creams containing vitamin C or azelaic acid in the morning to brighten your skin. At night, apply retinoids (like tretinoin) or glycolic acid, which help exfoliate and fade discoloration. For more stubborn spots, a dermatologist can prescribe a short course of hydroquinone cream. Always consult a doctor before starting new medicated creams to ensure they suit your skin type.