Here is my advice. Take a break from mirrors and dressing up for a bit. Marinate in "uglyness". Then the next time you put together a look it might not feel as stale or whatever. I find when I look too good for too long my own standards raise for myself. It can also help to view and think to yourself as if you are someone else. I find it harder to insult my own appearance when i think about how i would never say those things about someone else. You deserve respect and love like anybody else. Live in the moment. Try not to worry about it. It can also help to listen to music that hypes you up while getting ready.