普段は普段の見た目だよね。自分の顔をもって、人はその顔を見て自分を認めるよね。普段はあまり自分の顔を意識しないだろう。
Normally you look like whatever you look like. You've got a face, and it shows people who you are. You don't think about it much.
しかしたまに自分の顔を偶々見てしまうこともあるね。例えば鏡で顔が反射する場合とか、Skypeでしゃべっている際に自分の顔が画面の横の片隅に写っている場合とか。
But then there are times when you happen to see your own face. For example, when you look in a mirror; or, when you're chatting on Skype and can see yourself in the little window on the side of
the screen.
そんなときに顔を妙に整えてしまうね。
At these times, you arrange your face differently.
別の人になるね。
You become a stranger.