What are some objects that represent Melinda and her personality?
I am going to take this from beyond the text. A broken cosmetic mirror could represent Melinda. The cosmetic mirror is a symbol of beauty. People look in it to become more beautiful. The symbol of a broken cosmetic mirror reveals a distortion of that beauty. This represents how Melinda feels about herself. After her encounter with "IT" and the social ostracizing that went along with it, Melinda feels that her beauty has been distorted. She no longer feels as beautiful as she once did.
Another object that could represent Melinda is a broken cable box. The cable box is designed to unscramble a signal from the outside world and display it in a presentable manner to the public. After being raped, Melinda cannot unscramble any signal from the outside world. She cannot present an image to the world that she is fine and no longer finds the need to be "acceptable" pressing. This symbol represents how the experience has changed her and the view she has towards the outside world.
Finally, I think that the symbol of a bull horn might be effective in describing how Melinda is once she confronts "IT." When she asserts herself in "I said No," Melinda is "coming out" in a manner of speaking. She is announcing to the world that she is going to take ownership of what happened to her and appropriate it for herself. She demands that she is heard. Her announcement is akin to sounding a bull horn and calling out to everyone what her experience is and who she is from it. Her ability to "speak" is announced on this bull horn for all to hear and absorb.