That energy traveled back in time, becoming the very bolt of lightning that gave him his powers.
His mother’s death and his own accident become "fixed points" in time required to keep the universe running. Flash Theory: Barry Allen Creates His Own Villa...
In several comic runs (notably Secret Origins ), it is implied that when Barry died during Crisis on Infinite Earths , he turned into pure energy. That energy traveled back in time, becoming the
Barry did not just receive the Speed Force; he generated it through his own existence and sacrifice. 🏃 The Engine of the Multiverse That energy traveled back in time