baby face vs forehead

baby face

noun
  • A face, often chubby, resembling that of a baby; a youthful face. 

  • A person having such a face, especially a young man having a beardless appearance. 

  • A headlining wrestler with a persona embodying heroic or virtuous traits and who is regarded as a "good guy", especially one who is handsome and well-conditioned. 

forehead

noun
  • The part of the face above the eyebrows and below the hairline. 

  • confidence; audacity; impudence. 

  • The upper part of a mobile phone, above the screen. 

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