big spoilers for chapter 55 below !!
cain reaches in for a kiss to help jooin swallow the pill ( because he was half asleep but also running a fever ) that he needs so he wont be sick anymore, and as soon as jooin swallows it cain goes back in for another kiss and ends up leaving a mark on his lip ( from biting it ) and jooin wakes up fully being confused and then cain quickly brushes it off and tells him to rest and that he should feel better in the morning.
whenever jooin wakes up, he thinks it was a similar dream but was confused as to why it was with cain. jooin turns over and sees cain preparing breakfast for him and cain starts thinking if he should apologize or tell jooin the truth about the kiss and feels very guilty for it, but cain tells jooin that he should go take a shower and get ready for school. so jooin goes to the bathroom to shower and then comes back and it leaves us off on a cliffhanger with jooin saying "um... cain you know.."
hope this helped clear up everything :)
tyyyy (●'◡'●)ﾉ
spoiler?