Get back about a hundred too many (7)
I believe the answer is:
recover
'get back' is the definition.
(I've seen this before)
'about a hundred too many' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'a hundred' becomes 'C' (Roman numeral).
'too many' becomes 'over' (I've seen this in other clues).
're'+'c'+'over'='RECOVER'
(Other definitions for recover that I've seen before include "Get better; retrieve" , "Bring back" , "Rescue" , "comeback" , "get fit again" .)