I would be really annoyed over this but not to the point where it would cause me to be stressed/angry/etc. for over a day. Let's be real; she didn't soak down your Ferrari Enzo or Lamborghini Aventador. Even though we all are OCD about the cleanliness of our vehicles, at the end of the day, it is JUST a car. Life will go on. More important things will happen.
If it bothers you this much you owe it to both her and yourself to talk with your neighbor over it. Otherwise, you are ignoring a potential issue and how will you react the next time it happens? Address it now and be done with it.