scar tissue

scar tissue (usually uncountable, plural scar tissues)

1. (anatomy) A type of tissue found in animals containing a higher than normal amount of the protein collagen formed in a place where an injury has healed.
2. (figurative, by extension) The long-term psychological consequences of a negative event.
   • 2010, Kevin Leman, Sheet Music: Uncovering the Secrets of Sexual Intimacy in Marriage, page 32:

     So many people's lives have many broken relationships that have left behind psychological scar tissue.

• asteriscus