Answered by Shaykh Faraz Rabbani
What would you advise someone to do who committed zina a long time ago and although they have made tawba for it it still haunts them? Is there something else they can do to make up for their sin?

Walaikum assalam,
The person should be aware that true repentance wipes out the sin and its traces.
The Prophet (Allah bless him & give him peace) counseled more than one Companion:
“Fear Allah wherever you may be; follow up a bad deed with a good one and it will wipe it out; and deal with people with the best of character.”
This is the best of counsels, as it came from the Best of Creation (Allah bless him & give him peace).
Walaikum assalam,
Faraz Rabbani.