Acquire maiden maybe and become better after (3,4)
I believe the answer is:
get over
'become better after' is the definition.
(eg getting over an illness)
'acquire maiden maybe' is the wordplay.
'acquire' becomes 'get' (synonyms).
'maiden maybe' becomes 'over' (I've seen this in other clues).
'get'+'over'='GET OVER'
'and' acts as a link.
(Other definitions for get over that I've seen before include "master?" , "Deal with successfully, improve in health" , "Recover" , "Clear" .)