With Puck's reaction the emotionless mask fell. Nor was Loki able to hide her emotions again quickly enough. Surprise, confusion and surprise and a hint of...hope? Also something like despair--that this was unexpected and new for someone to be angry FOR her and not at her. She made herself take a deep breath, and only after that, did that mask go back up.

Before Loki turned to lean more into the hair stroking, hiding her face a bit, wanting and needing that comfort.