You pierced your own lip and its really swollen and hurts bad?

It is probably infected. If you pierced your lip with a safety pin or sewing needle, it is also due to hurt more because it should have been pierced with a hollow needle.

Rinse your mouth out with warm salt water after you eat. If the swelling does not go down, and it starts to ooze yellow/greenish liquid, remove the piercing and treat it like any normal cut or scrape.

It is better to get rid of it than to get a bad infection.