As someone who used to have BDD and an eating disorder, what helped me was focusing on my body's experience "inside out" and not on the various reflections/photos/videos of me seen from "outside in". You know what you really look like, to yourself. You see yourself with the eyes of the body you are. Seeing you from another's eyes is not "more accurate". It's just a different perspective, and by no means more important than your own.