Narcissists do not forgive or forget!
“Vulnerability in self-esteem makes individuals with narcissistic personality disorder very sensitive to “injury” from criticism or defeat. Although they may not show it outwardly, criticism may haunt these individuals and may leave them feeling humiliated, degraded, hollow, and empty. They may react with disdain, rage, or defiant counterattack.”
The narcissistic individuals I have known who have had this kind of injury reaction take a long time to get over it; they hold grudges, want to get back at the person they perceived harmed them; they seek revenge, try to cause problems for their attacker, and seem never to forgive or forget.