Remorse is like a dog biting a stone

Against remorse.—I do not like this form of cowardice in regard to one's own actions, one must not leave one's self in the lurch under the pressure of sudden shame or distress. Extreme pride is much more fitting here. What is the good of it all in the end! No deed gets undone because it is regretted, no more than because it is "forgiven" or "expiated. (make amends, redress) 

As a matter of fact, only a very small number of acts are typical acts and real epitomes of a personality, a single act very rarely characterises a man. Acts are mostly dictated by circumstances; they are superficial or merely reflex movements performed in response to a stimulus, long before the depths of our beings are affected or consulted in the matter. A fit of temper, a gesture, a blow how little of the individual resides in these acts!—A deed very often brings a sort of stupor or feeling of constraint in its wake: so that the agent feels almost spellbound at its recollection.
Enter remorse stage left

 The unfair interest which society manifests in controlling the whole of our lives ]
in one direction, as though the very purpose of its existence were to cultivate a certain individual act, should not infect us.
Nietzsche