Own the mistake, make it right, then stop punishing yourself. An apology is a fix, not a sentence.

Accountability has a shape: own it, repair what can be repaired, stop. Most people manage the first two and then get stuck in a fourth stage nobody asked for, where the punishing continues long after the fixing is done. That extra part adds nothing for the person harmed, and often leaves them managing your guilt.

If you have said it and mended what could be mended, decide the matter is closed on your side. When it comes back to mind, note that it was handled and carry on with the day. Doing better next time is the only piece still live.