acerbate vs get under someone's skin

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

get under someone's skin

verb
  • To irritate someone. 

  • To make a memorable impression or have a strong effect on someone; to impact someone's feelings, especially when such an effect is not expected or wanted. 

How often have the words acerbate and get under someone's skin occurred in a corpus of books? (source: Google Ngram Viewer )