Kept going and took action about blemish (9)
I believe the answer is:
sustained
'kept going' is the definition.
(I've seen this before)
'took action about blemish' is the wordplay.
'took action' becomes 'sued'.
'about' is an insertion indicator.
'blemish' becomes 'stain' (stain is a kind of blemish).
'sued' enclosing 'stain' is 'SUSTAINED'.
'and' acts as a link.
(Other definitions for sustained that I've seen before include "Long drawn-out" , "Steady" , "held up" , "Steadily maintained" , "prolonged" .)