He sure learns fast, and now he really might have learned to be cross with her for suggesting something like that. But you just can't tell with him.
Although, of course, it isn't so simple for things to go back just like that even if he's getting much better at acting. Honestly, it's pretty nice that Hyunsoo's friend didn't act like nothing happened. It's almost as if he was the only one who actually remembers her.