I can double check with the translator, but I'm almost positive that the tiny rebellion wasn't tripping and that it resulted in a whole ton of domestic violence, hence now living with her grandparents.
Actually the real cause of her injuries isn't much clearer in original than it is in TL (at least for me). I had a feeling that the author obscured this aspect deliberately as not to distract readers from the main story :) But then, Nami living with her grandma does make sense in case it was really DV.
Nami-san actually isn't hurt, she just bandaged up to get Juri-san's attention?
I'd rather say that she's hiding the fact of her recovery and keeping them on to have Juri by her side for as long as possible. So, in a certain sense, Juri's feelings are returned.