tbh i understand why people think he's double faced from this chapter but there's also this theory where he isn't human (zombie-like?) so kissing with someone who is made him have this reaction
That was my thought. Like whatever he is took over Guwon's body and that's why he's saying it in the mirror like that. I will trust the author that we'll get led down a great story-telling road with a happy ending. I'm here for it!
got that perv nosebleed