Face full of Lies
A person who lies so much their face is like a billboard saying 'I'm lying, and I'm proud of it.'
My neighbor said she didn't borrow my bike, but her face looked like she just stole it.
My friend said he didn't copy my essay, but his face was like he was trying to escape a prison.
My sister said she didn't eat my lunch, but her face was like she just won the Super Bowl.