Castiel felt no embarrassment at having his worst fears laid out for him, for this Dean. They were amongst the fears of all angels.
He frowned in concentration as if he could dredge up the lost memories by sheer force of will. When he could not he dropped his eyes to the floor and pressed a hand over the knot in his chest.
"What do I do?" his voice was wretched. He looked up at Dean, "Tell me something. Tell me something we did."