Kat feels as if she's waking up; seeing Archie's life and lolly's death from a new perspective. She wishes sometimes that she had never seen her own face in the mirror.
If you think about it, humans make themselves have uses nobody needed, and feel attacked when told so because of our denial. This is the perspective of a middle schooler: the insignificance of caring.
Lolly meets a someone, or a version of someone, she was fortunate enough to have never seen before. Kat knows she won’t see them much longer. (Disclaimer: this chapter may gross some people out)