Nanjo cleaned him up and put the d back inside, there is no reason to go that far just for revenge, he simply missed that d. Whether that extends to Mokyeon as a person too will have to be seen, because for now Nanjo just showed his sexual interest, but taking him to the hospital and bringing him back and cleaning him up after sex are not something you do to someone you just want to use imo

Did you realize Nanjo is taking revenge word by word, action by action. I suggest you to re read the whole thing since the very beginning. And support the authors.