Spoiler alert!
I don’t think so. In chapter 39 he blushed when that tailor touches him by the sides while measuring. That’s a hint that it really is because of the medicine.
Maybe some kind of aphrodisiac?
He was blushing because they were talking about Seungho.. he wasn't given an aphrodisiac or anything like that. He was given a version of antipyretic medication..
It's obvious Nahkyum is developing some sort of attraction for him, hate it or not, it is what it is
He didn't blush because of that. He blushed because they mentioned seungho.
╮(￣▽￣)╭ I know they were talking about Seungho but I don’t think they weren’t saying anything that should cause Nakyum to be blushing over. Also the scene with the servant specifically asking the doctor for the medicine seemed suspicious with the way he acted. Guess we’ll just have to wait till it’s revealed.
The medicine is not making nakyum feel some type of way... the reason he didn’t want to drink it is because he thought that it was, so when he was brought to seunghos room he was all blushy & when seungho painted him he got horny and said “this is all cause of you my lord” ¯_(ツ)_/¯