After Regret

Regret:
Many people who experience regret often find themselves saying "I wish", wishing they could turn back time to change or fix something, particularly words that may have hurt someone close to them or to avoid an embarrassing situation. They believe that their lives would be different and better. But does regret still have a place in today's world? I see the wounded waiting for their doctor to prescribe them medicine, and the only prescription they seek is the two words "I apologize". However, the injured have become lifeless, and neither the doctor nor the apology has arrived. How many times will I say "sorry" to myself after enduring years, months, days, and sleepless nights of sadness?

I spend countless hours and minutes dwelling on past situations and my unforgettable reactions. How can I forget when I'm awake until dawn and beyond, constantly pondering the question:
What comes after regret? Does one simply succumb to regret and offer an apology, or is it more complex than that?
Is regret more complex than just offering an apology?