A specialist is someone that has chosen a single field of expertise and who devotes themselves to perfecting that one area. In the body art industry, there are either tattoo specialists (those that only do tattoos) and body piercing specialists. While there are many body artists that are proficient in both disciplines, it is becoming more and more common to see tattoo artists that only tattoo and body piercers that only pierce.
Just as you would expect the best service possible from the service department of the dealership where you purchased your car, you can expect the best body piercing experience possible from a professional body piercer that specializes only in body piercing, and who has spent their entire career perfecting each kind of piercing technique to the point they are considered masters at their craft. If you are fortunate enough to have such a body piercing specialist in your area, you can expect only the best body piercing experience possible, and you will have the highest chance of having your body piercing turn out exactly the way you wanted it to.