I can somewhat relate. I don't often look in the mirror, and when I do look in the mirror its usually at something specific (my eyes, skin, etc.) and I focus intently on it. It makes me look vain, but I'm actually only focused on that one thing - not my beauty as a whole.

Every so often, i'll look at myself as a "whole" in the mirror and I don't feel like it's real. I feel like i'm inside of a shell. And i'll find myself making faces and movements trying to "outwit" my reflection. Sometimes I feel so "put inside of a body" that I touch my face to try to match feeling senses with my visual senses.

Never usually works though, and I tend to just shrug it off. Thanks for bringing this up!