face up to vs undergo

face up to

verb
  • To confront a condition or situation, typically one that is unpleasant or uncomfortable. 

undergo

verb
  • To suffer or endure; bear with. 

  • To experience; to pass through a phase. 

  • The project is undergoing great changes. 

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