@michimonsterr,
I'm not sure there are too many "skins" in this forum (let alone ones who have a familiarity with inked genitals) to satisfy your specific inquiry.
It doesn't take a genius to figure out that scarring a region of the human body that is designed to have a relatively execssive number of nerve endings is going to hurt like a bitch.
I can't imagine that your fellow inked would have any advice on this subject other than "Make sure your labia is tattooed by someone who knows what he or she is doing."
There is no reason to believe that injecting ink under the skin of ones's labia is any more dangerous that doing so with an arm.
If you were contemplating a lung or brain tattoo, maybe the answer would be different.
I also can't imagine that very many male tattoo artists will turn away the chance to work on a woman's genitals unless the woman is physically repulsive, and even here I suspect that in the world of skin art, what is considered repulsives doesn't quite match up with the standard for "Norms."
I can't for the life of me understand why you would want to have your labia inked, but they are yours and, if you do, go for it.
As long as you aren't turning your face into some approximation of a hideous demon I don't think you need to worry about the psychopathy of tattoos.