Last night when I got Hermine the mouse out I noticed that she has a bald area on one side of her face, it starts just below her ear and stops at her chin. What on earth could it be? It doesn't look sore. I have no idea how long she has had it as for once I was wearing my glasses. A few weeks ago Beatrix her cage mate had some fur loss just above her nose. I didn't worry to much as it looked as if she had been rubbing and it has completely cleared up.