Ablative lasers are usally used for the treatment of the top layer of the skin, like face, lips, chin etc. The ablative laser needs some time to recover the problem. Non ablative lasers: "A non wounding laser, which stimulates the collagen growth and tightens the underlying skin”
Lasers are painless and safe methods that targets and attracts the darkness on the lips. You need 2-4 sessions of treatment based on how much your lips are dark.
Low strength glycolic peel or a fusion peel of glycolic, citric, kojic and mandelic. It's usually recommended by many that you protect these areas with vasoline before treating so that they are not over affected.