fester vs rile up

fester

verb
  • To cause to fester or rankle. 

  • To become septic; to become rotten. 

  • To worsen, especially due to lack of attention. 

noun
  • The condition of something that festers; a festering; a festerment. 

  • A sore or an ulcer of the skin. 

rile up

verb
  • To rile; to aggravate. 

How often have the words fester and rile up occurred in a corpus of books? (source: Google Ngram Viewer )