Responses
It wasn't necessarily because of the kiss. It just happened after... probably it wasn't like he kissed and then immediately ran to the toilet so some time passed.
Everyone forgets that we know little of the world, the dead are coming back to life, the "father" telling that his son is just ill and acting sus, there's a few other reasons for Guwon to throw up other than he didn't like the kiss.
I hope that's the case, idk if my heart can take the angst. I also found the dad acting super sus when he didn't let the MC see his son, i wonder what was up with that.
Chapter 13 he was throwing up over a kiss (potentially) but now they're doing the hanky panky? I cant wait to see how this unfolds.