Maybe if she decided to go on missing him, no matter what, Tally could keep her mind from changing. Unlike most people, she knew about the lesions. Maybe she could beat them. (50.43)
Can Tally hold on to her memories so tightly that she doesn't lose her identity? We're doubtful (and we can't wait to read the sequel), but we understand why she would hope that: losing your identity is pretty much the worst thing (even worse than losing your hoverboard). But note the connection Tally makes between memory and identity, that she can keep her identity if she keeps her memory and the feelings for her friends.