Six-line Wrasse Question

[DACJ]

My sixline has always been a beauty, and I liked how it's mouth is like a beak...;however, recently I've discovered that the "beak" is not as sharp or not as pointy as it looked before, I told my wife, but she said it had always looked like that, and I thought maybe cause it grew a little bigger in size, or that may also be the reason.

Now, I just got home, and for the first time I see the reason why her mouth is not as pointy as before, in fact, I'd like to say, her mouth is damaged...
She has been attacking? or nibbing on the tank glass for sometime before and after I got home, and I assume she has done it before to result in the shape of mouth changing, has anyone had this issue before? I am seeing the lower part of mouth with a little white color, afraid it is badly damaged already, but I don't see any "food" (any kind) on the glass, so I have no idea why it is attacking the glass...