Is there a word to say when someone frowns anxiously? Example: You just wrote a song and sang it for the first time for your best friend. By the end of the song you look at your friend, unconfident and with your forehead wrinkled and eyebrows on a /\ shape, anxious to hear his opinion about it.
Facial features are complex and often display mixed emotions. You could use words like "contorted" or "paradoxical" to describe the facial feature(s) that you want highlight (along with anxiety) for the best resulting effect.
"I looked at her anxiously with a contorted frown (or smile) to receive her response, but the paradoxical strain on her brow gave it all away."