What is the difference between a Labret Piercing and a Lip Piercing?

The Angle that the piercing is done at.

A Lip Piercing is pierced almost vertically with the natural curvature of the lip. This means that the jewelry is less like to come in contact with teeth, bone or gums. Thus meaning less chance for damage. Also you have more jewelry options then a Labret piercing. You can wear a ring, curved barbell and even a Labret Stud.

Labret piercings are pierced almost horizonally or perpendicular to the tissue. In other words straight through below the lip. This cause increase chances of contact with gums, teeth and bone. Due to the angle and the fact that the jewelry would have to wrap around the lip, rings are not an option. Also a barbell may in fact cause more damage. So you are limited to either a Fishtail Labret or a Labret Stud.

Placement is also a factor. A lip piercing is just below the lip, while a labret is much lower depending on the jewelry type in the shape of the mouth.