The piercing is actually 2 small semicircular slits in your skin. Your body builds up a tunnel of scar tissue between these 2 slits in a process called epithalisation. As long as your immune system is working properly, and there is nothing in the piercing that can irritate the fragile new cells, your body will HEAL ITSELF.
Your piercer should take extra-ordinary measures to ensure that there are no irritants in your piercing. The piercing must be made using a sterile needle, the sterile jewellery is made of materials that do not react with your body and a special no touch technique should be used so that contaminants are not passed between people. This means that IRRITANTS CAN ONLY BE INTRODUCED DURING CLEANING.