No, Hypnosis is not dangerous at all. It is a natural state, everyone goes into the state of hypnosis without knowing several times a day. Just before sleeping or for some time just after awakening you are in hypnosis. When you are on a long drive on a highway, you are in hypnosis, your eyes are fixed on the road, listening to the music when someone give a horn for side, you automatically give him side without being aware a little. You also apply brakes or blow horn whenever necessary.
When you are watching an interesting movie, you are in hypnosis. When you are playing or watching your favourite game, you are in hypnosis. When you are reading an interesting story, you are in hypnosis. In hypnosis you are relaxed and focused, that’s it. So be assured, hypnosis is not dangerous at all.