I think i get it this part where all doyeon's arm are now covered with scratches, she starting to scratching more to herself, i related this a bit like when you get faced alot of your problems lately and you always get exhausted and sometimes you noticed your mental health is getting unstable, it's not like she has mental illness it's just we don't know much what really caused of his prolonged stress lately but i bet she was exhausted of thinking about new problems everyday. Let's hope she doesn't hurt herself more.