To get her used to misting, there are things you can do.
First, start out by just spraying the bottle in the same room, to desensitize them to the sound. When she seems fine with the noise,
you can also spray yourself next to her cage and go 'oooh aaah' and make a nice fuss about it. When she's used to it more, you can spray into the cage, but not on her. Then, once she seems used to it, you can finally spray above her so that the drops fall down like rain. Don't do it rapidly; don't want to freak her out too much. Just do a squirt or two at a time. She'll probably get mad, but if you followed the steps above, it should make it easier on her. Hope this helps!