Hurt/comfort fanfiction can build vulnerability and the pain inflicted on the body might stand in place for abstract hurts. This creates the tension, in this case, the hurt part of the story structure. In identifying the release or comfort part, it might be useful to look at an interpersonal and intrapersonal answer.
Rachel Linn defines the horrifying h/c that focuses on the body in pain and a sense of self, this is a story about
the hurt character coming back to themselves.
Linn, Rachel. 2017. “Bodies in Horrifying Hurt/Comfort Fan Fiction: Paying the Toll.” Transformative Works and Cultures, no. 25. http://dx.doi.org/10.3983/twc.2017.1102.
In other stories, the character’s journey might not change but the focus is on their relationship with a comforter character. In this interpersonal story, the vulnerability serves not only the hurt character getting to know themselves better but deepening their relationships.
The comforting character acts as an anchor through which the hurt character can recognize how pain is shaping their world and change that power’s direction.
Linn, Rachel. 2017. “Bodies in Horrifying Hurt/Comfort Fan Fiction: Paying the Toll.” Transformative Works and Cultures, no. 25. http://dx.doi.org/10.3983/twc.2017.1102.
In h/c, transmission is unnecessary—the comforting character understands, though no one else does.
Fathallah, Judith May. 2011. “H/c and Me: An Autoethnographic Account of a Troubled Love Affair.” Transformative Works and Cultures, no. 7. https://doi.org/10.3983/twc.2011.0252.
These moments of vulnerability and connection are sometimes in direct answer to hurt inflicted in canon. Fandom is certainly uniquely equipped to pair the hurt we see with the comfort we create.