Reversing memory damage (3)
I believe the answer is:
mar
'damage' is the definition.
(thesaurus)
'reversing memory' is the wordplay.
'reversing' is a reversal indicator.
'memory' becomes 'ram' (RAM is an example).
'ram' back-to-front is 'MAR'.
(Other definitions for mar that I've seen before include "Make imperfect" , "Blemish" , "Cause harm" , "Oh dear!" , "Ram into and spoil" .)