Hello, Darkening or hyperpigmentation of lips can be due to smoking, alcohol drinking, eating fried and unhealthy foods etcetera. Other causes can be an excessive intake of coffee and tea, excessive sun exposure, allergy, too much use of lip cosmetics that have harsh chemicals, dehydration etcetera. So, my suggestion is to start applying vitamin E gel over your lips. You can also apply kojic acid containing creams that help in lightening dark lips. You can do ice massage over the lips, rub a piece of ice over the lips either directly or after covering in a piece of cloth. It improves blood flow and lightens the darkness. You can also exfoliate your lips by using honey and oatmeal mixture. It can be gently scrubbed over the lips. Drink plenty of water. Use sun protection lip balm when going outside. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Honey Arora