How to mirror/copy changes to other side of mesh

Hi! I am working on making a shape key for my mesh to blink. I did one side and am now trying to duplicate the changes to the other side. Is there a way I can just copy everything from the left side of my mesh and apply all the same changes to the right side?

I know there is a mirror option but the vertices on the right and left sides are slightly different due to previous blinking iterations so I was hoping to just copy everything over.

toggle this!