Lips are particularly susceptible to moisture loss because the skin is thin and they are exposed to the elements more so than other parts of your body.
Coconut oil is a mainstay in alternative medicine for treating burns. This is due to its moisturizing and analgesic (pain-relieving) properties. A chapped, cracked lip can also benefit from these properties.
Coconut oil is also considered to be an emollient. Generally, emollients are non-cosmetic moisturizers that help keep the skin moist. These tend to work best immediately after bathing because they trap moisture in your skin. Nevertheless, you can apply them throughout the day as necessary, especially if you consider your lips, which lose moisture more quickly than the rest of your body.