Well, then, first... First Sight and Second Thoughts. People think that magic is about having second sight, but second sight is more about not thinking about why something would mean what it does. First sight is taking it for what it is and then wondering what it would mean. Second thoughts go, "Why would it mean that?"
So, I would first consider why you believe that this is an evil spirit. Because what I would think it COULD be is...
1.) Something in your energy body that is not supposed to be there, like an elf arrow, a meridian blockage, or a coagulated little curse-tumor sort of thing. Psychic surgery, just what it sounds like, removes this thing that is not supposed to be there.
2.) Something in your energy body that should be there but is not. A soul shard... that's all I can think of. Sometimes, traumatic events can cause parts of our souls to splinter off and float around in some magical otherworld, and healers that specialize in putting people back together will do just that. Sometimes a sign of a soul-shard lost is memory loss!
3.) If it IS an entity, or dissociated autonomous intelligence, or some...I don't know, shadowy alternate personality taking over, then please do check with a professional. This isn't to say that it is not magic, only that this is another approach to solving this troublesome experience that you can also take.
Have you researched what I'd listed outside of psychic surgery? The hematite, the banishing rituals? Just pick which one you feel would work best, because (this should have been the first thing you said) you're closer to what's happening to you so you can see it more clearly than I can. So, reserve your right to your own opinion.