As a subject matter expert...we have to take in the whole pie on this one. A tattoo is ink placed in the upper most part of the dermis, wherever on the body. But..here are some facts, there are two genres', the face and the body. Different inks and pigments, different machines and techniques. Permanent cosmetics professionals understand the stretches for the areas, the needles clusters to be used for the best effects, and proper placement of the pigment for lip tissue. Lip tissue heals differently then the rest of the body, and if your prone to cold sores, you can have a herpetic outbreak. There are proper protocols for comfort and artistry, as well as healing. Given all these factors, a tattooist that does traditional body art can do it, if he has had some formal training as relating to the face. But, if.. he has not, steer clear as you are not his experiment for his career. Its best to leave the face to certified technicians, check out credentials, and references. After all its your face and you dont want to pay for the rest of your life for a whimsical notion.