She does stay. In fact, she sticks around the house for the next couple of days, trying to take care of Wash and keeping him company. It's no surprise when she starts feeling crappy. She's not sick yet, but she can feel it coming on, not that she says anything to him, because she's too worried to. His fever is getting worse, and she's starting to worry that this might turn into something serious.

"How are you feeling?"