He could see them as badges of honor. Naruto has always been a character who doesn't shy away from a fight. So, he might embrace the scars as proof of his battles and growth. He would show them off as a sign that he has overcome difficulties.
Maybe he tries to hide them at first. Naruto might be worried about how his friends and the villagers would react. But as time passes, he realizes that they are a part of him. He then starts to use them as a motivation to become even stronger. He could also use his scars to inspire the younger generation of ninjas, telling them that every scar has a story and that they should not be afraid of getting hurt in the pursuit of their dreams.
In some fanfictions, Naruto might initially withdraw into himself. He could focus more on his training to distract from the pain. For example, he might go on long solo missions or intense training sessions in the woods, away from the reminders of Sakura.
Naruto could also become withdrawn for a while. He might isolate himself from his friends and spend time alone, reflecting on what went wrong and trying to heal his broken heart on his own. During this time, he might also start to question his self - worth.
One possible backstory could be that he endured intense and brutal training sessions that left him scarred. Maybe he was training in a forbidden or extremely difficult jutsu that required him to push his body to the limit. Another could be that he got into numerous battles with powerful enemies without proper medical treatment afterwards, causing the scars to remain.
Naruto might initially feel sad and confused. He could try to prove himself to his friends by working hard on his ninja skills. For example, he might train extra hours to show his friends that he is worthy of their attention.
In the fanfiction, Naruto might use his chakra control skills to create a genjutsu that alters the perception of those who see him. He could project an image of his unscarred self over his actual body. For example, he focuses his chakra on the area around his scars and manipulates the light and the way it reflects off his skin in the eyes of others, making the scars seem to disappear.
One possible reason could be that he doesn't want others to pity him. Naruto has always been a proud and strong - willed character. His scars might be a reminder of painful past experiences, and he prefers to deal with them privately rather than showing vulnerability to others.
In some fanfictions, Izuku deals with being expelled by seeking alternative training methods. He might find a retired hero who is willing to train him privately. This way, he can continue to develop his skills and prove that he is worthy of being a hero.
Spiderman could call for help from his superhero friends or use his knowledge of science to create a makeshift treatment in fanfiction. His quick thinking and resourcefulness would come into play.
Naruto might also face hatred by becoming stronger. He trains harder and shows his opponents that he is not someone to be underestimated. For instance, if a group of rogue ninjas hates him because they think he's too idealistic, he proves them wrong by defeating them in combat and showing that his ideals are what make him strong.
He might try to prove himself. Naruto has always been a determined character. So he would likely strive to show his family that they are wrong about him. He could do this by achieving great things in the ninja world, like mastering new jutsus or completing difficult missions.