Carrie is a heartbreaking character. Her mother is so horrible I just wanted to reach through the book and punch her. I found the fact that Carrie still loved her mother even though she abused her terribly, and that she even made excuses for her mother's behavior authentic and real. This is something I've learned about in my foster parent training - the biological tie between a parent and child is very strong and children will still love their parents after almost anything, frustrating as that can be to people trying to help the child.

I was a little bothered by a few things that seemed unauthentic and pulled me out of the story. One of them is when Carrie is severely beaten up by her mother and goes to Cricket's house. Cricket's dad, a police officer, is there along with the rest of Cricket's family and even though Carrie is in and out of consciousness, no one suggests taking her to the hospital. I would think a police officer would know better than that.

Also, the very ending did not seem realistic to me. That's all I'll say because I don't want to spoil it for anyone. But if you've read it, I'd love to hear what your thoughts are on the ending.
Other than those quibbles, I really enjoyed this book. It was the kind of book that I walked around in a fog thinking about when I had to tear myself away from reading it. It's full of surprising plot twists. The book alternates between Carrie and Honor's point of view. I thought the author did a good job writing Carrie's point of view - I know it can be hard when the narrator is so young.
This book didn't have as many charming Southern idioms as most of the Southern fiction I've read, but I'll quote my two favorites:*

"And she's being as sweet as honey on a pretty girl's finger."

"they'll haul you out of here so fast it'd bring tears to a glass eye."

This book is being marketed as a stand-alone novel but it has the same characters from Elizabeth Flock's novel Me & Emma, which I have not read. I didn't have any trouble following What Happened to My Sister and I agree that it can stand alone. However, knowing that there was a previous book out there made me really curious about what Carrie's life was like before she and her mother left Hartsville. I'm going to have to read Me & Emma since I enjoyed this book so much.
*quotes are taken from an uncorrected review copy – the final copy may differ