The Butterfly Effect is a 2004 American science fiction thriller film written and directed by Eric Bress and J. Mackye Gruber, starring Ashton Kutcher and Amy Smart. Synopsis: A boy experiences blackouts and memory loss throughout his childhood. Later, in his 20s, he finds he can travel back in time to inhabit his former self during those periods of blackout, with his adult mind inhabiting his younger body. He attempts to change the present by changing his past behaviors and set things right for himself and his friends, but there are unintended consequences for all.

References:
https://en.wikipedia.org/wiki/The_Butterfly_Effect