Hannah lifted her head and saw Seo Joon's flustered expression. "What? Why are you looking at me like that? Does it hurt?". Her gaze was very innocent, the moment that Seo Joon got pricked by the shell, she panicked and didn't think much anymore; forgetting that she was putting up an act.
Seo Joon couldn't tell her what's wrong because he too was surprised by what she just did with his finger and to top it off, in front Samantha and Daniel.
Hannah had been very secretive about their relationship whereas Seo Joon really didn't care if his sister knows about them. But since Hannah wasn't ready to reveal it yet, then he was going to just let her continue.
But with the situation now, he doubted that Hannah can still keep up with it.