That mark on her nose looks like the little rub marks dolls can get when their noses rub against the top of their box. My Kailey has a faint one, and my Kaya had a really bad one when I first took her out of the box. I did a wash with baking soda, like you did, and it made it much less noticeable. It's still there, but by now I just think of it as a distinguishing feature that makes Kaya my own. I'd try the suggestions here about the sandpaper and the magic eraser if you want it gone completely - I've heard great success stories about both of those cleaning methods.