Dean took a moment to digest the news, and then, before speaking, turned the bottle up and had a good deal more. It was easier, to drink rather than talking about things like this, easier to give himself the excuse later at being drunk out of his right mind if he said something that was too incriminatingly soft-hearted.
He had not been there for Sam, he had not been there for Jo, and they went through hell because of it. Not that either of them really needed a keeper or babysitter, but because of his choice, Dean wasn't there to deal with his possessed brother. He didn't regret the result of his deal, that Sam lived, but he wondered if there had been another way that he had missed, something that he could have done that would have let Sam live and not cost his own soul in the bargain.
"I owe you one." He said simply, his eyes looking her over in concern to see if she was still in any pain. "And I appreciate you keeping it from Sammy, but, if you get your ass kicked again, I want to know." Just like with the bar owner, Dean remembered things, and he always found a way of making sure those in his 'family' were taken care of.