We have all felt abandoned or rejected at times, and most of us get over it with a little time and processing of our feelings: We move on. But the narcissist does not. Narcissists are not enough in touch with their own feelings to move on. The issues remain in their mind as "it's all your fault," or "How could you do this to me?" They want to strike back and seek revenge. While they may not act arrogant and haughty and put on a show that nothing bothers them, this facade makes it difficult for others to see their inward self-loathing. They do not have a solid, developed sense of self so we see them swing from depression to grandiosity with little in-between. Their presentation deceives most people until they get to know the narcissist. When the narcissists' facade of charm and deception gets cracked, their whole world bursts apart. They will blame others for their feelings of inadequacy, lack of happiness or success, and lack of love.
Karyl McBride Ph.D., "Understanding Narcissistic Injury," Psychology Today, October 25, 2020