In Speak, what does Melinda do to the mirror?

In the book Speak, main character Melinda Sordino has been the victim of a rape. Throughout the novel, she is attempting to deal with the social and emotional outcome of the rape and, of course, is having a very difficult time. One symbol that is particularly present throughout the course of the book is that of mirrors.  
After the assault, Melinda begins to hate mirrors. Every time she sees a mirror, she feels disgust for herself, for the image that she has become. She has taken to nervously chewing on her lips and picking at them, and this causes her to shy away from her own reflection, sinking even deeper into self-loathing. At one point, she goes shopping alone, relieved to be by herself.  Yet, when she goes into the dressing room, she feels horrified at her own image in the 3-way mirrors; She has gained weight, and she says she can see “reflections of reflections, miles and miles of me." She adjusts the mirror so that she looks like a Picasso painting (chapter 14). 
Finally, she gets her revenge on both her rapist and the mirrors which she so despises.  In chapter 89, towards the very end of the book, she is followed to her secret closet in the school by Andy Evans, the boy who raped her at the party. He threatens her, accusing her of lying and telling her that he will "give her what she wants" (chapter 89). Instead of retreating into herself, she decides to take action, throwing something at the poster of Maya Angelou, one of her heroes, and breaking the mirror behind it. This momentarily startles Andy away from his attack. Grabbing a piece of glass, she holds it up to Andy's neck. Finally, he is the one who can't speak—not her.