look back

/L UH1 K B AE1 K/
verb
  1. 1

    To reconsider or regret.

    โ€œYou do what you have to do, and don't look back.โ€

noun
  1. 1

    A look in a backward or retrospective manner; an additional or secondary look; a review.

Source: https://en.wiktionary.org/wiki/look%20back, https://en.wiktionary.org/wiki/look-back