Well, in this kind of fanfiction, this scene can have a huge impact. If it's written well, it can completely reshape their relationship. Harry might feel a sense of gratitude towards Snape, which is something he never thought he'd feel. Snape, on the other hand, might feel a strange sense of connection. It could be the start of a friendship or at least a more amicable coexistence. It also gives the writer a chance to explore the psychological aspects of both characters, like Snape's guilt and Harry's capacity for forgiveness.
There could be a fanfiction where Snape finds Harry unconscious with blood on him after a skirmish with some dark wizards. Snape's actions of washing the blood off are not just about cleaning but also a way to symbolize his internal struggle between his hatred for James Potter and his growing, albeit grudging, respect for Harry. This could lead to a complex character development arc for Snape in the story.
It can potentially start to thaw the icy relationship they had before. Just this simple act of physical contact might make Harry see Snape as less of an enemy.
The healing might make Harry feel indebted to Snape. This could change their relationship from one of animosity to one where Harry is more open to Snape. Snape, on the other hand, might still be his usual guarded self, but the act of healing could create a crack in the wall he has built between them. Harry might begin to question his previous assumptions about Snape and be more willing to cooperate with him in certain situations.
He could be secretly worried. Snape might use his knowledge of potions and dark magic to try and find a cure or at least a way to stop the bleeding. He may also be conflicted, as his past relationship with Harry and his loyalty to different sides in the wizarding world play a role in how much he wants to help Harry.
It would change it drastically. First, Snape would have to come to terms with this new relation. He might start seeing Harry not just as James Potter's son but as his own family. This could lead to him secretly mentoring Harry, guiding him in potions and in dealing with the darker aspects of the wizarding world. Their relationship could shift from animosity to a sort of guarded kinship, with Snape being gruff on the outside but having a newfound soft spot for Harry.
In fanfiction, their relationship can develop in many ways. Sometimes it starts with Harry being suspicious of Snape as in the original books, but then Snape shows his selfless side. For example, he might save Harry from a dark spell and that starts to change Harry's view.
It often shows a power - imbalanced relationship. Snape, being in a dominant position, can bring out both fear and respect from Harry. Harry may initially rebel against Snape's dominance but gradually learn from it.
At first, it's likely to be very tense. Snape has always had a grudge against Harry because of his father. But as they live together, they start to see each other's true selves. Harry might see Snape's vulnerability and intelligence, while Snape might see Harry's courage and determination that are different from James's arrogance.
Often, it starts with intense dislike. Snape is constantly critical of Harry in class, deducting points for the slightest mistakes. Harry, in turn, sees Snape as a bully. As the story progresses, there might be small moments of grudging respect, like when Harry realizes Snape's intelligence in potions, but the overall hatred remains for a long time.
At first, it could be very tense. Harry might be reluctant to submit, but as time goes on, he starts to see Snape in a different light. This could lead to a grudging respect. For example, Snape might show Harry some advanced potions techniques that no one else has taught him, which makes Harry realize Snape's value.