I'm not sure what exactly you mean by "on the side" - a cracked lip is a cracked lip, and it does not really matter where it has cracked, at least as far as treating it goes. The best treatment is applying aloe gel to the affected area, and in fact to the whole lip. This is extremely soothing, and will help the crack to heal more quickly. Aloe gel is quite easily available at any medical store, and even at most general stores today. However, fresh aloe gel is a lot more effective, and if possible this is what you should use. You can simple break off a bit of an aloe plant, take a little bit of the gel that is released, and gently rub it on your lips. Rubbing a cucumber slice on the affected part of the lip is also supposed to beneficial. Both these methods are primarily useful because of the cooling, soothing effect that they have. Healing of the crack however will occur on its own, and nothing really needs to be done for it. Depending upon how badly your lip has cracked, it should heal in a couple of days, or at the most, within a week. If this does not happen, or if the lip becomes particularly painful or swollen, you should visit a doctor.
While your lip is healing, you should avoid consuming substances that could irritate it, such as spicy foods and alcohol. If the injury is in a location where it is possible for you to avoid contact with these substances by exercising caution when consuming them, then of course there is no need for you to abstain.
A cracked lip is usually the result of dry, chapped lips, and this is a problem that you should address, unless of course your lip cracked as a result of an injury. If you frequently suffer from dry lips, you should first of all ensure that you are drinking enough water. You can also apply lip balm, preferably unflavored, unscented lip balm, or even a plain, glossy lipstick - this will help your lips to retain moisture. Avoid licking your lips constantly, as this will provide only temporary relief, and will in the long run worsen the dryness. You should do these things right away, as keeping your lips moisturized will help the crack to heal faster. If your lips stay dry, the crack will take longer to heal and will be more painful.
answered by G R