Is her eye injury supposed to happen when Fujiwara tells her to go home, or before? It doesn't look like he hit her or anything, just probably tossed something at her that hit her?
He hit her during sex or whatever it was before that scene.
In any case, both Fujiwara and Hotaru appear to be pretty worthless as humans beings. Yuma needs to tell Hotaru that she won't be a "cheating partner". She will either be a partner or a friend, if neither of those are options, then they will be neighbors and that is all. In other words, she needs to tell her how she felt when she saw her with Fujiwara on the trip!
Well, actually Yuma is Hotaru's "cheating partner" from the start. She is pretty dense, so she didn't know that what she was doing with Hotaru is cheating. Probably, because she thought that flirting and kissing with a girl doesn't count. Overall, you can interpret last page of chapter 5 as Hotaru's twisted love confession.