Have him go out with her again maybe even just the next date they're planning at the end here) and finally decide to work up the courage and tell her he likes her and wants to date her for real, only for Himeno and her friends to show up. Tobita cheerfully greets them and chats with them, and maybe they even notice him and start to talk to him, only for him to start trembling and then congratulate Tobita on her determination, keeping up the act for so long and putting on such a convincing show all for a stupid dare. But if the dare's over now then that's enough, she doesn't have to see him again; she tries to call out to him and he tells her he means he doesn't WANT to see her again). A while later, Himeno comes to find him. Maybe with a bruise or two, perhaps a black eye. She apologizes for what she did, but also berates him for not realizing that Tobita wasn't acting. After enough apologizing and lecturing, he accepts both and goes to find Tobita and make up. Maybe find her soaking her fist in cold water.