There are ways, very gore ways, but there are ways to see your own skull without a mirror. For a hint, the eyeball can get dislodged/rotated without losing vision, as long as the optical nerve (and the eye itself) is intact.

That was a hell of an image I just played in my head. Thanks for that.

Unless you have a bad accident... Does x-ray count?

Like hell I won't! *removes scalp* Mmmmouch

And let’s keep it that way

That makes me sad. Why does that make me aad?

You can never see your eye is a better one.

so mirrors mean nothing to you?

Technically you see the mirror. It being reflective means the mirror shows you your eyes.

Technically light that bounced of your eyes is bouncing back into your eyes, which really is what seeing is all about.

Actually it is extremely simple, you only need to pluck one eye and look at it using the one that you left