As someone who has been on the receiving end of someone's paranoia based on my alleged "microexpressions", please do not assume that you necessarily are always right about how other people are feeling or whether they're dishonest. It could very well be that you AREN'T preternaturally gifted at this the way you think you are and you are capable of making mistakes. If that's the case, it's gaslighting to tell someone you know what they're feeling better than what they say they are.
My stepmother did this to me, telling my dad that she "knew" I wasn't genuine and disliked her, because apparently she didn't like my microexpressions. The thing is, she was completely wrong. I would fucking HATE some self righteous "hyperempathic" person to tell me they know my emotions better than I do or tell me I'm being dishonest based on their flawed reading of my face.