If Castiel had told her that he had the ability to heal her she'd consider the possibility that he could (and likely go into a long tangent about it) before agreeing to attempt it. But for that to work they'd have to broach the topic, and where she came from they didn't have angels with healing abilities (that she knew of) so she certainly wasn't going to bring it up.
"People tend to respond to a person in a position of authority," she agreed. Her chest started to heave as the cough hit her and she was quick to pull a wad of tissues out of her jacket pocket to put up against her mouth. The last thing that she wanted to do was cough up blood all over a perfect stranger. After roughly a minute she regained her composure and shook her head, answering his question as she daintily wiped at her mouth with the tissues: "No. You're the first person I've seen." She was trying to keep a cool composure, but inwardly she was completely freaking out.