Well all I know is that sometimes scars can fade. I had a scar on my chin for years and one day I looked in a mirror and I couldn't find it. Maybe the same thing happened to Nastya.
I agree. As a little girl I had a scar on my forehead as well. Oddly enough, my mother saw to it that I wore bangs throughout my childhood. It was a horrible scar too - I smashed my head against the metal corner of a TV stand - it required many stitches. I wear my hair pushed off my forehead now, and sometimes I forget completely that a scar ever existed there. I'm 32 now and the scar was about 25 years ago. Once in a while if I get too much sun, the area of skin will get a little more pink and you can see the outline of the scar. Other than that, I often forget about that scar.
I have no problem believing that Anastasia, as a little girl (and a tomboy at that) got a scar on her forehead that her mother decided needed to be hidden by her hair. By the end of her life, it had probably faded to the point that if you didn't know it was there, you didn't see it.