Dean knew as soon as he made a sound that it was a mistake. He'd let it slip and now she knew she could make him repeat it. And he was right. She immediately cast a spell at his hand, encasing it in water and freezing it solid.
A moment of panic flared in Dean. That was his right hand. His wand hand. More importantly, his painting had. If anything happened to it...He swallowed back the fear, trying not to let out another sound. For the moment, fear and worry kept him mute.