Judging from his fatigue from the start of the chapter, I think this is a rare instance where this isn't the lethal Japanese cold, but instead a proper fever that he's been battling for a few days.
@Tamerlane
I'd agree with that. Although I still don't think any of them have much in common, other than having played together as kids, idol at least has a more similar personality in her private life, being more quiet and reserved.
Glad the idol girl realizes she's on the backfoot and need to fight.
Also, Japanese Cold OP, need nerf. One splash and BOOM you're almost in the hospital.
FFS Japan, you don't get a cold by being wet or cold. Although he did appear fatigued at the beginning to maybe he caught it on the trip. That would make more sense anyway.
Ya boi was sick before the splash, he just felt the chills more after getting splashed with cold water.
On side note, can Yuriko just lose already, hands down, I'm getting tilted at her very presence in the manga.
I also get the awful feeling we're going to have some extras joining the harem/ship too... Nisekoi 2.0 here we go