hydroquinon topical lotion is a medicated treatment that lightens areas of darkened skin (hyperpigmentation) caused by sun damage, pregnancy, or other factors. It works by disrupting melanin production, the pigment that determines skin color. Applied twice daily to affected areas, it can be effective but can also cause dryness, irritation, and increased sun sensitivity. For these reasons, sunscreen use is crucial and consulting a doctor before use is important.