Speak is great. It also deals with trauma and recovery, but is less harrowing and more funny. (Wintergirls meets Prom?)

I haven't read Chains but have heard good things, I enjoyed Twisted when I read it but can now recall nearly nothing about it, and I didn't like Fever.

I too love the liminal quality of Wintergirls. You might also check out Kathe Koja's Blue Mirror, which is more clearly fantasy but shares some similar gritty lyricism.