It is not recommended to use strong skin-lightening creams on your lips. The skin on your lips is extremely thin, delicate, and sensitive compared to your face. Active lightening ingredients can cause severe irritation, peeling, dryness, or allergic reactions in this area, and there is also a risk of accidentally ingesting the product. For dark lips, it is much safer to use a deeply hydrating lip balm with SPF protection to prevent sun-induced darkening. Please consult a dermatologist who can evaluate the cause of the pigmentation and recommend safe, specially formulated treatments designed specifically for the lips.