To prevent further darkening, daily use of a broad-spectrum sunscreen with SPF 30 or higher (and PA+++ protection) is essential. Look for sunscreens containing physical blockers like zinc oxide or titanium dioxide. For treating existing darkening, creams containing active ingredients such as Vitamin C, Niacinamide, Kojic acid, or Azelaic acid are highly effective at gently fading pigmentation and evening out skin tone. This darkening is a very common, natural response to sun exposure and is easily manageable. Please apply sunscreen daily, even on cloudy days, and consult a dermatologist if you need a customized treatment plan.