on Writers Helping Writers:
In this series on pain, we’ve covered everything from minor injuries to major and mortal injuries. But there’s another source of pain that can push our characters to the edge of coping: invisible injuries and conditions.
When readers see a bruise, cut, or gunshot wound, it’s easier for them to fill in the blanks about what happened, and imagine the pain that goes with it. But when the source is internal, writers have to work harder to connect the dots for readers, especially if the character themselves is unaware of what’s causing their distress, or they choose to mask their pain.
Chris The Story Reading Ape's Blog 