Many People assume that every time a bump appears on there piercing that it is a Keloid. This is called an infection. A Keloid is hard and raised they produce a bulky formation of scar tissue under the skin. This will spread beyond the boundaries of the piercing. They can also become very large and painful.
Keloids are often hereditary and are more common in people that have a dark complexion.
They are very difficult to treat. Another form of scar tissue is Hypertrophic scars, they tend to be fleshly and stay within the boundaries of the piercing. Affected piercings may appear to have protrusions of soft pink skin at the entrances of the piercings. In some cases they are known to reabsorb as the piercing heals or the irritation is eliminated. These are more common in people with fair complexions.