[escape_thereal_world]

You could do tree branches, wind (cloudy streams coming off the bats and going down your back),

Not sure if this could work for you, but you could do something like this where there are large bats surrounded by smaller bats. You can also see some 'wind' marks, which any professional tattooist should be able to help you come up with a nice idea of how to extend the wind.

And of course, stars would work too!