Steven could get hurt while experimenting with his powers. He might push himself too far in an attempt to discover new abilities or to use his existing ones in a more powerful way. This overexertion could lead to him getting physically or mentally hurt. Also, he could be hurt by a Gem who has a vendetta against the Crystal Gems and targets Steven as a way to get back at them.
One scenario could be that Steven is exploring an unknown area and stumbles upon some sort of dangerous trap that causes him harm. It could be a hidden energy field or a collapsing structure. Another possibility is that he gets hurt while trying to protect his friends. He might jump in front of an attack meant for someone else, like Connie or the Crystal Gems, and bear the brunt of the injury.
One common theme is the display of friendship. As Steven is sick, his friends rally around him, showing how much they care. For example, they might all take turns staying by his bedside. Another theme could be self - discovery. Steven might learn more about himself and his limits while being ill. He realizes that he can't always be strong and that it's okay to accept help.
Some possible what-if scenarios could be what if Steven never discovered his gem powers or if the Homeworld had a different strategy for attacking Earth.
A fanfiction could be written where Steven gets hurt in a more emotional way. For example, he discovers some dark secrets about the Gems' past that are so shocking it causes him mental and emotional pain, which in turn affects his physical well - being. His friends notice the change in him and try to help him come to terms with what he has learned.
A possible scenario could be that they are at a beach. The waves are crashing gently in the background, and as they look into each other's eyes, they share a tender kiss. It could be a moment of pure, unspoken understanding between them.
It could be a new villain that has emerged. This villain might have some sort of vendetta against Steven specifically, perhaps because of his unique powers or his role in the gem world.
It depends on what you mean by 'hurt'. If you're referring to the story or characters, it might not necessarily hurt it. But if it's about the popularity or reception, that could vary depending on the changes made.
Adventure is also a common theme. They go on different quests or face various threats together. This could be something like exploring an ancient gem ruin on Earth or fighting off a new enemy. The theme of acceptance is important too. Accepting each other's flaws and differences. Amethyst accepting Steven's sometimes naive view of the world, and Steven accepting Amethyst's wilder side.
One great 'Steven Universe Hurt' fanfiction could be 'Beneath the Surface'. It delves deep into the emotional turmoil of the characters. The author does an amazing job of portraying their pain and the struggle to overcome it. Another is 'Shards of Pain' which focuses on the aftermath of a major battle and how the characters deal with their physical and emotional wounds.
One interesting scenario could be Baby Pearl getting into Steven's room and playing with his toys. She might find a stuffed animal and start having a conversation with it as if it were a real friend, imagining all kinds of adventures they could go on together.