Controlled studies of acupuncture in pediatric patients have shown its usefulness in managing nausea after surgical removal of tonsils and adenoids and following eye surgery to correct strabismus. It has also been shown to help reduce chronic headache pain in children. Just how acupuncture works is not well understood, but it may stimulate the release of neurotransmitters such as endorphins and serotonin or otherwise inhibit pain transmission.

http://www.ucsf.edu/news/2014/04/113966/acupuncture-helps-young-patients-manage-pain