spoilers
In the light novel (if my memory serves me right), Jiwook got into a situation and got injured, which led to him getting amnesia. The thing Jiwook did to Jooyeon was SAing him when they were kids after Jooyeon confessed his feelings. Jiwook also shared the video to Jooyeons mom, which caused her to become mentally unwell.
i think it’s just for the plot yk? jiwook forgot EVERYTHING about jooyeon from when they were kids, but he seems to get “flashbacks” of kid jooyeon and remembers some other people. i think something he said in the novel was, “i don’t remember much that happened in high school besides getting into fights.”

what im confused about is why did jiwook forget what he did? does he just have shitty memory or something? someone spoil me please