Polishing Animation Blueprints

Hello, fellow game_makers, I have a question for some of the intellectuals among you.

I am making an FPS game with arms I cut off (using blender) from a Paragon skin. It went surprisingly quite well except the left hand was hovering underneath the gun. How do I change this? I tried opening the mesh and simply dragging a hand up, but it didn’t change anything (except, of course it elevated my state of confusion).