First attempt to post a story on LJ -- no clue what I'm doing. My older story fits this prompt perfectly, so I had to try. I hope this works.

Summary: Immediately following the departure of Thor and Loki with the Tesseract, the healing process begins for Clint. As he considers her scars, he wonders how Natasha can ever trust him again. 1,300 words

http://www.fanfiction.net/s/9374732/1/Invisible-Scar