He's well aware how awful he looks, though they may have differing definitions of what they mean by 'awful'. He's also not sure how to go about this, since he really doesn't know what Barry might have told her about him. It's not a memory he can access, as if it happens it hasn't happened yet.

So he stares at her for a moment, hopefully not a long and creepy moment. "Do you know what a temporal duplicate is?"