Her hand, film vs book

[Rebecca]

Ok in the film there is a bit where she cuts her hand on a railing and they do a close up and because you speak movie you assume something will happen (maybe she'll get tetanus or someone will think she is self-harming and put her in solitary or something.. but no..), it doesn't come up again.. and it's mentioned nowhere in the book that I can see... so w00t? What's that about? What do you think?
Hypothesis:
(view spoiler)[
I know her hand is an important plot-driver in the film because the fact she had a delusion that the bones in her hand were broken helped justify the decision to institutionalize her, so maybe that moment of looking at her injured hand gave her a moment of clarity and strength and allowed her to tell Jared Leto to go borrow some else's eyeliner because she had better friends now. (hide spoiler)]

[Kaylie]

When she and Toby were fighting she looked down and saw that she had been clenching her hand and her fingernails dug into her palm. So it was to show how conflicted she was about whether or not she should go with him, also confirming that she still had problems that she needed to work out at Claymore.

[Rebecca]

Really? I swear I saw her scrape her hand off the railing and injure herself that way, I watched it with someone else who also saw that. Maybe we watched a non-standard cut of the film?