Had to double check the whole eyebrow thing and yeah, it checks out. She's been raising her eyebrows every time she lies. Props to the mangaka for keeping it consistent.
I don't know about that, with how often she 'raises her eyebrow', it could be about anything she said up to this point. Not only a 'bad liar', but a malicious one, at that. I'm not even going to bother checking previous chapters to confirm that fact as I just don't like her enough to even care about that sort of detail. What actually worries me is that when she said she 'doesn't care about Kimiya anymore', we
didn't see her eyebrows there, so we don't even know if she was telling the truth there or not.
And honestly, about that 'being lied to' thing by her fans ... girl, those things you worry about when you're dating a guy. When you're in the show business/idol industry, you're selling yourself to be someone's source of entertainment for a brief moment. Almost everyone has more than one source of entertainment, and in some cases, they'd rather pick reading books than following idols every time, and it isn't abnormal for a person to follow multiple idols or music artists (it's actually those that are dedicated to one person at a parasocial level that you gotta watch out for, Kimiya's one of the exceedingly rare types who knows where he stands as a fan and Urumin as an idol).
If you're going to make a fuss over who's loyal to you as a fan, you're better off doing something else other than the idol industry, because humans are temperamental creatures have quite the short-attention spans. You're just shooting yourself in the foot if you're going to continue seeking 'loyal fans' as you have been.