This is an extreme lip piercing shown here with a CD worn as jewelry. Its not only lip but also the ears are also stretched, as seen in the picture.

Stretching is a long process and should be avoided when the piercing is not fully healed.If the skin around the piercing gets very thin then stop stretching. The easiest way to thicken the tissue is to downsize a few sizes, wait a couple of weeks, and then re-stretch.