
Spoiler !
It was never confirmed if the tea made him sick, but he gets really sick to the point he needs medical attention, but he still does his test in the end regardless of his state of well being and does amazing. Everyone gets worried about him and thinks he did poorly on his test because he was so sick, but he does very well on the test !!!
Also there's no raws that I have on me sadly, I read this story on a Korean novel sight translated to poor English long time ago

A lot of these cliche fighting stories lack a lot of common sense in terms of finding the truth, even though it's a female lead, I would love to see her be smart & sneaky in term of finding the answers to her sisters rape, while keeping her temper and fighting spirit. The author did a disservice to her character to only make her combative. It seems to be the plot of most fighting stories where they fight everyone to the top and everything turns into fist fight when there seems to be a problem, I just wish there was better plot device then just fighting. I wish there was a bit more, because I'm reading the raws and it seems that this story is all about fists and not any common sense
I'm so glad she told him !!!