In this kind of fanfiction scenario, Snape might initially be conflicted. On one hand, he has his long - standing dislike for James Potter, Harry's father. But on the other, his sense of duty as a Hogwarts professor could kick in. He might reluctantly start to heal Harry, all the while muttering under his breath about how much trouble Harry always seems to get into, just like his father. Then, as he heals Harry, he might start to see some of Lily, Harry's mother, in him and soften a bit.
The theme of facing new challenges is also prevalent. His injury might lead to new magical problems or encounters with dark forces that are taking advantage of his weakened state. This forces Harry to think outside the box and use different strategies to protect himself and those he loves.
One great injured Harry Potter fanfiction is 'Beneath the Surface'. In this story, Harry gets injured during a particularly dangerous battle with dark wizards. The author does an amazing job of showing his struggle to recover both physically and mentally. Another one is 'Healing Wounds', where Harry's injury leads to some unexpected friendships as he recovers in the Hogwarts infirmary. It delves deep into the relationships between the characters.
In some fanfictions, Harry might take the injured owl to Hagrid. Hagrid, being an expert with magical creatures, would then tend to the owl's wounds. He might use various potions and spells to heal it. For example, he could use a healing charm that he learned from his time at Hogwarts or some special herbs from his garden.
One possible plot development could be that his friends rally around him. They might search for rare potions or spells to heal him. For example, Hermione could be scouring the library for ancient healing magic while Ron stays by Harry's side, offering moral support.
It could be a rogue Death Eater who managed to catch Harry off - guard. Maybe they were lying in wait and launched a surprise attack when Harry was alone, away from the safety of Hogwarts.
Snape could be very cold at first, but then his natural instinct as a healer (since he is quite good at potions which are often used for healing) might take over. He might give Harry a potion to ease the pain and start to patch him up. All the while, he would probably be scolding Harry for being so reckless and getting into a situation where he got injured.
Many times, the author will describe in detail the magical healing process. They might introduce new spells or potions to heal Harry. Also, they'll show how Harry's injury affects his ability to perform magic, which adds an interesting layer to the story. For instance, if he's injured his wand arm, he may struggle with spell - casting. And his mental state due to the injury is also explored, like if he has nightmares or fears of getting hurt again.
He might first try to calm the owl down. He could use a soft voice and gentle magic, like a simple soothing spell. Then he'd carefully examine the injury. If it was a broken wing, he'd try to splint it with a small stick and some cloth.
One great fanfiction is 'The Wounded Hero'. In this story, Harry gets injured during a battle with a new dark wizard. The author does an amazing job of showing his struggle to recover while still facing the threats around him. It also delves into his relationships with his friends, who are all trying to support him in different ways.