You are angry at your son, because he is selfish (your interpretation).
You feel neglected by him (your experience).

The first Tap Sentence you could start with:
Even when my son neglects me, I still accept myself

It may stop here, after having tapped this several days twice a day you may not feel hurt anymore. But it is most likely that this experience is only at the surface of a deeper feeling.
Let us assume after four days you do not feel any relief at all. There is a big chance that you had memories from the past during tapping. These memories tell you that nobody has ever liked you. You feel even more depressed than before tapping. Now it is time to jump on to your interpretation: nobody has ever liked me.

So the next Tap Sentence is:
Even when nobody likes me,
I still accept myself

You are even feeling depressed by only reading this sentence. You start doing the tap sessions and day after day the sad feeling from this sentence diminishes. After four days you even feel relieved. And you are not any longer annoyed by your son’s behavior. You have let it go and you are aware that either your son’s behavior is your interpretation or it is his attitude. You cannot blame him for the way he is feeling.