No. We cannot find any instance where anyone has been harmed by hypnosis. It has been noted that after most hypnotic sessions, clients report that they sleep better at night and are more relaxed during their daily life.
What if You Can't Bring Me Out of It?
There is no danger of a person failing to come out of the hypnotic state. In fact, it would be impossible to remain hypnotized. Even if the hypnotherapist left the office while an individual was in the hypnotic state, there would be not danger. The person would drift off into a natural state of sleep and would awaken after he was rested.