I had a similar situation with Corkscrew and my roommates cat Sasha. Sasha was just terrified of Corkscrew, the only time she felt safe was when she was locked up in the bedroom. We lived together for 2 years and she never got over it. Just the sight of Corkscrew was enough to make her start screaming and hissing. She lost a lot of weight and somedays was so stressed out she couldn't poop. When I went to visit her at her new place (my roommate and I both moved into seperate apts.) she was like a whole new cat. I couldn't belive it was the same cat that I lived with for two years. She was so sweet and playful and very happy. So I learned that sometimes cats just don't get over it. But I wish you the best of luck with whatever you decide.