I'm resonably new to AE and I'm editing a video where the guy pulls a scoped gun up to his face, and I was wondering if there was a way to have only the scope lense get brighter as he pulls it up to his face. Thank You For Your Help.
This sounds like a job for a duplicated layer in conjunction with either an animated mask or an animated track matte, either of which can isolate the glass in the scope, which you can then boost in brightness.
Since you're new to After Effects, I recommend that you work your way through the basic learning materials. If you do so, such tasks as this will be obvious to you, since you'll have the basic building blocks of compositing and animation.
BTW, here are a couple of videos in which I show how to have an effect only apply to one item in a scene: