Office Politics Ruining Chances of Return Offer

Currently an intern and I'm starting to think I won't get a return offer. Although I got very good feedback from everyone else before the official review, I got a very bad mid-summer review because one analyst who doesn't like me for some reason shat on me in the review process. Every time I get staffed under him, he refuses to delegate work to the intern even after asking multiple times and just does everything himself, so I have no way to demonstrate my technical abilities. On top of that, I got negative comments from him on vague behavioral things that are obvious lies and it's clear he's spreading rumors about me to other analysts. I'm very frustrated with the situation and don't know what to do. Should I start looking elsewhere? I'm very worried that in this environment, I might not be able to get a FT offer outside, especially if I don't get a return.