The National Center for Complementary and Alternative Medicine, a division of the National Institutes for Health, states: “Acupuncture is generally considered safe when performed by an experienced practitioner using sterile needles.  Relatively few complications from acupuncture have been reported.  Additionally, there are fewer adverse effects associated with acupuncture than with many standard drug treatments (such as anti-inflammatory medication and steroid injections) used to manage painful musculoskeletal conditions like fibromyalgia, myofascial pain, osteoarthritis, and tennis elbow.”
The World Health Organization confirms:
“In competent hands, acupuncture is generally a safe procedure with few contraindications or complications. “
According to evidencebasedacupuncture.org, “acupuncture is amongst the safest interventions in modern medicine with the frequency of occurrence of serious adverse events at 11 per 4,441,103 procedures” and that “acupuncture remains one of the safest contemporary treatments available.”    However, it is noted that “acupuncture must be performed by qualified acupuncturists”.
Minor side effects may include slight bruising at the acupuncture site occasionally, or a feeling of fatigue.  Both should subside very quickly.