Questions about the movie Thirteen

After all of the craziness, drugs, fighting, etc. Tracey is just spinning on a merry go round and screams. I kind of wish they had ended the movie differently.

Can anyone tell me their explanation of the symbolism? All interpretations are welcome.

Also:

Why did Evie kiss Mel on the lips? I thought it was very odd

Was Brooke actually Evie's cousin or was she lying about that too?

Was there any symbolism behind Brook's plastic surgery?

Why did Evie tell the psychic/social worker that she was the one just trying to make things better?