You could have been trying to hide things, but because your mind knows it's not the same it might have affected your subconscious so you weren't actually working as hard hiding it as you thought you were. You might not even be aware of it.
[He says, pressing his lips together in a flat line, scratching his cheek - mind works in strange ways, and someone's subconscious sabotaging attempts to hide something isn't the strangest thing.]