When you see yourself being hypnotized in a dream, then it shows your fear to be known by others. The dream could also be a symbol of someone in your waking life who is controlling you a lot, especially if you are the one who is hypnotized.
Dream dictionary: Hypnotize dream meanings
…Dreaming of a large, handsomely dressed crowd of people at some entertainment, denotes pleasant association with friends | but anything occurring to mar the pleasure of the guests, denotes distress and loss of friendship, and unhappiness will be found where profit and congenial intercourse was expected. It also denotes dissatisfaction in government and family dissensions. To see a crowd in a church, denotes that a death will be likely to affect you, or some slight unpleasantness may develop. To see a crowd in the street, indicates unusual briskness in trade and a general air of prosperity will surround you. To try to be heard in a crowd, foretells that you will push your interests ahead of all others. To see a crowd is usually good, if too many are not wearing black or dull costumes. Dreaming of seeing a hypnotist trying to hypnotize others, and then turn his attention…
…will be nonplussed to distinguish your friends from your enemies. For a woman to think a child places one on the back of her head, and she hears the snake’s hisses, foretells that she will be persuaded to yield up some possession seemingly for her good, but she will find out later that she has been inveigled into an intrigue in which enemies will tantalize her. To see snakes raising up their heads in a path just behind your friend, denotes that you will discover a conspiracy which has been formed to injure your friend and also yourself. To think your friend has them under control, denotes that some powerful agency will be employed in your favor to ward off evil influences. For a woman to hypnotize a snake, denotes your rights will be assailed, but you will be protected by law and influential friends. See Serpents and Reptiles….
To hypnotize a person indicates that your influence will be very strong on those around you. To be hypnotized predicts that you will have to submit for lack of power.