What happens if you change your lip piercing to early and it grow over your backing?

Four Words: GO TO YOUR DOCTOR. Embedded body jewelry can lead to serious complications and any reputable piercer won't touch them. It requires opening the skin back up to remove the embedded metal and the FDA considers this a medical procedure therefore it is illegal for piercers to do so. You have to go to the doctor immediately. If you don't you could suffer from serious infection, the metal could migrate and you could potentially cause damage to your mouth area or hinder your eating/speaking ability.

There's a reason piercers are adamant that you do not touch a new piercing until it has completely healed over!