Cas isn't in the room, unfortunately. But he does return shortly (again) with a bucket of ice since this motel miraculously has a working ice maker.

Retrieving a towel from the bathroom, Cas fills it with ice, wets the scratchy terrycloth just enough to make it damp and twists it closed. He sits on the edge of the bed and pulls Dean's arm into his lap, resting the ice on the center of the bruise.