Face full of Lies
Someone who lies so bad their face is like a broken traffic light, all red and wrong.
My friend said he didn't cheat on the test, but his face was like he was about to cry.
My dad said he didn't break the lamp, but his face looked like he was trying to hide a crime.
My brother said he didn't eat my snack, but his face was like he just saw a spider on his toast.