I wouldn't go out of my way to denounce myself. You don't make the system more honest by doing so and just get labelled as an idiot.
It depends of course what the qualification is for. If you cheated on a pilots exam then you should make an effort to cover all the safety related skills again before they let you fly solo. If you cheated in a Medieval Agrarian History exam, who cares? The burgers will taste just the same.
Why not just accept the next injustice that comes along in life without compliant and offer it up in reparation?
For sure something will cross your path. Forgive an unpaid debt, or don't react when someone treats you badly.
You don't always need to manufacture your own cross, as there are lots lying on the road ahead of you.