A change from pink to dark pink lips is often caused by hyperpigmentation, sun exposure, dehydration, or a mild allergic reaction to lip products. Before using medicated ointments, try these safe steps: 1. Sun Protection: Use a lip balm with SPF 30 or higher daily. 2. Hydration: Apply pure petroleum jelly (Vaseline) or coconut oil frequently. 3. Avoid Irritants: Temporarily stop using scented or flavored lip cosmetics. Do not apply strong skin-lightening creams without a dermatologist's prescription, as they can cause permanent damage. If the color change is accompanied by peeling, itching, or pain, please consult a dermatologist for a proper evaluation.