Artist's touch-up (3)
I believe the answer is:
dab
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">artist's touch-up</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for dab that I've seen before include "Gently wipe" , "A bad, backward fish" , "Light stroke" , "[SOMETHING FISHY]" , "Apply light touches of colour to the fish" .)