We all have unpleasant encounters from time to time, and we all replay these unpleasant scenes in our heads and get angrier at the other and ourselves. It does no good except waste energy and make ourselves miserable. Try and look at it as if it was happening to someone else, so you feel less insulted, threatened or violated, and therefore less prone to fear/flight emotions.

Was it a valid complaint - in which case the right thing to do would be to make amends. Like it or not, we have to live with our neighbours. Was the complaint false - best leave it perhaps, with luck it will blow over, especially as you said it was trivial.