All I can say is make sure the person knows their stuff.
I had a guy who had apparently been practising for 15years, put a needle into a raw nerve, and I have never experienced anything as painful. I was screaming at him to take it out...and then the next time I visited him, he did it AGAIN. He said that had never in all his time happened, and he'd never seen it before. Guess I just got lucky, but maybe PTSD and the emotions and pain from my experience was so intense that the needle triggered something that wasn't ready to surface?
I'm sure it wouldn't happen to most people though, so I don't mean to scare you, but that was my experience with PTSD and acupuncture. I have had other times of having acupuncture that have been tremendously relieving and really got my energy flowing tangibly again, so it does work. Just make sure you are with someone you trust and who has been doing it a long time.