fester
/ˈfestə(r); `fɛstɚ/ v[I]
1 (of a cut or wound) become infected and filled with pus （指伤口）溃烂, 化脓
a festering sore 化脓的伤处.
2 (fig 比喻) (of feelings or thoughts) become more bitter and angry （指感情或思想）更加痛苦和愤怒
The resentment festered in his mind. 他心中的愤恨有增无已.