Festered (7)
I believe the answer is:
rankled
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">festered</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rankled that I've seen before include "Embittered" , "caused persistent annoyance" , "Festered" , "Annoyed" , "caused constant annoyance" .)