Laws about acupuncture practice vary from state to state and right now, only about 40 states have standards for certification.
Speak with your doctor or ask at your local clinic if they have any recommendations. Word of mouth is a good way to find someone that is trustworthy. Once you've found an acupuncturist, visit the office and ask questions about hygiene and safety. All the disposable needles should be one-use only and come from single sterilized packages opened just for you, and your skin should be cleaned with an disinfectant before treatment begins.