Here's why:
* Gauge: Earring gauges (the thickness of the post) are measured in millimeters. A smaller gauge (like 16g) is thinner and may be too small to stay securely in a lip piercing.
* Post length: If the post of the earring is too short, it may not be long enough to go through the piercing and have a comfortable amount of backing.
* Shape: Some earring styles, like studs with very flat backs, may not sit comfortably against the inside of the lip.
It's important to choose earrings that are the right size and gauge for your piercing. If you're unsure, it's best to consult with a reputable piercer. They can help you select earrings that are safe and comfortable for your piercing.