Lip service?

Yes, they're interesting and can be a lot of fun, but THEY WILL FADE AWAY.

Why Does a Lip Tattoo fade so quickly?
The skin in your mouth replaces itself faster because the acid and abrasive, food digesting chemical content peels it way. The mouth is an under appreciated part of the body. You can't live without it. Your lips, teeth, gums, and jaw all work together to keep you alive. You should thank the spirits by making sure that you brush your teeth and visit a dentist regularly; so you don't end up having a molar rot out and need a root canal just to quell the stench and then have a greedy dentist put in a fragile porcelain crown only to have it shatter a few months later and then pay another honest, old skool dentist, who tells you rinse with salt water, more money for a shiny GOLD crown which looks and feels awesome but kinda makes you a pirate.

Solid gold tooth or not, if you get an inner lip tattoo, you will need to have it touched-up/re-inked from time to time. When you are getting the tattoo, you can expect to savor the lusty taste of blood, pigment, soap, and a touch of hipster douche-bag. It is nothing to worry about. You'll want to stay away from color, especially yellow or red, which may contain trace amounts of poison or not.

What's the point of a Lip Tattoo?
You get to show a few people close enough to smell the cheetos on your breath that you can spend money on a tattoo that isn't really permanent. So, the point ISN'T the meaning or fashion statement; it's the laugh, the eye-roll, or the "that's cool" that will make people want to read your lips.