He took her lack of answer as a distinct no, meaning it probably bothered her enough that she didn't want to worry Justin with it.
Something they obviously had in common.
"No nightmares," he said with a shake of his head, "but... something happened." He paused, and looked her in the eye. "I'll tell you mine if you tell me yours."
Never would anyone have thought he could say that phrase without a quirky grin or a waggling eyebrow.