Melinda becomes a great big woobie once you realize why she's so quiet and isolated. Everyone hates her for what she did at the party, and Andy (the cause of her suffering) is the jerkass of all jerkasses to her, knowing quite well that she's near-mute.
And then it comes full circle when Andy decides for a round two.
Melinda finally works up the courage to Rachel that the reason that she called the cops at the party was because she was raped. Rachel believes her...until Melinda tells her who did it. It's Andy Evans, Rachel's boyfriend.