The resolution of Melinda's narrative is an empowering one.  Melinda learns to assert her voice both internally and externally.  She no longer blames herself for the assault and anything that resulted from it.  She is able to "speak" in terms of warning Rachel about "IT."  When she is confronted by her abuser, she is able to stand up to him by asserting that she said "NO!"  He recognizes this and has to capitulate, as other members of the student body respond to Melinda's voice.  As Melinda stood up to "IT," she has gained respect from her peers.  Most importantly, she has been able to gain a sense of self respect for who she is and what she represents.  

Mr. Freeman approaches her and opens himself up to listening to her narrative.  The ending is one in which she sits with her art teacher and presumably shares her experiences of the past year.  In this resolution, the major issues of the novel have been brought out and resolved as Melinda has been able to assert her own voice in carving out her identity and who she is in the world.