Is it always the same hand that's moves on its own? Do you also find that you have two distinct personalities some of the time? Have you had surgery prior to the symptoms?
Since you posted this under BPD community, I'm assuming you have borderline personality.... Borderline Personality Disorder really affects a person's perception of what's real and what's not. I promise you that nothing is taking control of your hand, but it might be that you're losing awareness of your thoughts and actions. It could be that you're moving, or touching your eyes, in reaction to a dream, but of course you will never be able to know that.
From a medical point of view, your hand can not move without a signal from your brain. I'm sorry I can't give you the answer that you were looking for, but that's also a sign of anxiety, which it seems you have. Some people do different things that they're unconscious of doing when they're anxious (biting nails, pulling hair, itching, picking skin, shivering, or shaking). I wouldnt be too worried if I were you. Just try to work on staying grounded.
Great! thanks Sanna. I will try to improve my self.
Good answer :)