Can taking Xanax cause brain damage?

I am 21 and have PTSD. As a temporary solution for extreme panic attacks I've been getting, I was prescribed Xanax for occasional use until I can see a doctor again. It's been two months and I have found myself taking it more and more. And I've noticed my train of thought in general is not as clear. My short term memory is awful. I am not as sharp as I normally am. But at least I do not feel like I'm burning in a fire of self-hatred and terror all the time - but when it wears off it comes back. I fear I could get addicted. Will Xanax use permanently damage my brain? Is it a worthy tradeoff, to have a slightly impaired short term memory than to feel hellish all the time..?