Depending on how severe it is its often possible to polish it out
with tripoli and rouge, or just zam. You will probably find that once
you have gotten the surface optically smooth you still see a ghost of
the damage. My guess is that the nacre is ‘bruised’ and the aragonite
xtls have shifted orientation or broken… You might be able to work
around this with creative setting. But still the pearl is damaged and
you might want to price it accordingly.
Nacre thickness will be a big factor in how aggressive you get with
it. Don’t be ham fisted though, keep cool.