I think most of us are like this. We go to the bathroom, and as we're washing our hands afterwards, we catch sight of ourselves in the mirror, and think "I need a haircut." or "Is my face really that colour?" or we remember that we've always hated our eyebrows ...
The psychologist I am seeing suggested that I try to develop "positive mirror talk." Look in the mirror and think something nice about yourself. I will not tell you what I thought of this idea, but I will tell that I have ever been one to do what she's told to do. So I tried it.
It took some work. I finally stopped thinking about the physical attributes at all, and started to just lean forward, look deep into my own eyes, and say "I like you.", with the kindest smile I could muster up.
Sometimes I had to do it more than once, because I'd catch sight of my profile or my hair that was too flat in that one spot or some other such horror - but I'd do it. As many times a day as I went to the bathroom - lean forward, eye contact, "I like you", big smile.
And then something started to shift. I'd be walking out the door, towards something that might be challenging and I'd remind myself "Do the mirror thing." And I'd walk out the door just a little bit lighter in my heart.
And now when I walk past a mirror, I don't avert my eyes so that I don't see some hitherto unnoticed failing.
The mirror has become friendly, and the world a friendlier place. Today I walked into the bathroom and before I even got to the mirror, I felt a tiny surge of appreciation, because I knew what was coming.
So try it! Lean forward, make eye contact, be kind to yourself.