It could be related to some sort of magical interference. Maybe there are spells or enchantments in the room that are affecting his vision, making him squint. In fanfiction, this could lead to an interesting plot where he has to figure out how to counter these magical effects while also dealing with whatever else is in the room, like hidden secrets or dangerous creatures.
The squinting could symbolize his uncertainty. He might be in a new and unfamiliar place, and squinting shows that he's not entirely sure what to expect. For example, if it's a room in a wizarding inn he's never been to before, the squinting is his body's natural reaction to the unknown environment.
In fanfiction, his squinting could be a sign of a deeper emotional state. For instance, if he's in a room that reminds him of a past trauma, he might unconsciously squint as if trying to block out the memories associated with it. Or it could be that he's just extremely tired, and the squinting is a simple physical manifestation of his exhaustion as he tries to take in the details of the room.
It might also indicate a newfound curiosity. Fanfiction often takes characters in different directions. Harry could be squinting at Malfoy because he's starting to see a different side of him. Maybe he's noticed something that makes him think Malfoy isn't all bad, and the squint is his way of trying to understand this new Malfoy better.
It could be a sign of distrust. Harry has always been suspicious of Malfoy's actions and motives, so the squinting might be his way of trying to figure out what Malfoy is up to.
One possible fanfiction idea could be that Harry Potter squints as he enters a mysterious room filled with strange artifacts. Maybe it's a hidden chamber in Hogwarts that he stumbles upon, and the dim light makes him squint while he tries to figure out what each object is and what their significance might be.
It could be that Harry has noticed some strange behavior from Malfoy. For instance, Malfoy might be acting secretively around certain areas of Hogwarts. Harry's squinting is his way of observing Malfoy closely to find out what he's hiding.
In many fanfictions, Harry Potter squinting at Voldemort could be a sign of intense focus. It might be that Harry is trying to read Voldemort's next move, or perhaps he's looking for some sign of weakness. For example, in some stories, Harry's squinting could be related to his newfound magical abilities that he's using to analyze Voldemort's magic signature.
In the fanfiction, Harry squinting at Wormtail might also be a moment of intense focus. Harry could be trying to use his Legilimency skills (if he has developed them in the fanfic world) to read Wormtail's mind. He's squinting as he concentrates, trying to break through any mental defenses Wormtail might have. It could be a crucial moment in the story where Harry's discovery of Wormtail's thoughts could change the course of events.
The plot could be that Harry is kidnapped by a vengeful Death Eater who survived the war. This Death Eater wants to use Harry to bring back Voldemort in a new form. The squinting part could be due to a curse the Death Eater placed on Harry to limit his vision and thus his ability to escape. Harry has to rely on his other senses and his past experiences to outwit the Death Eater.
A simple plot could be that Harry's glasses break right before an important exam. He has to squint to read the questions, which makes it really difficult for him. His friends try to help him, but the examiner doesn't allow any outside assistance. Harry has to dig deep and rely on his memory of the material to get through the exam. In the end, he passes, and it shows his determination.
It could mean a fan - made story (fanfiction) where Harry Potter is looking closely or suspiciously at a snake. Maybe in this fanfiction, the snake has some special significance, like being related to Slytherin or having some kind of magical power that Harry is trying to figure out by squinting at it.
One possible fanfiction could be that Harry Potter is kidnapped by a dark wizard who has some strange power that makes Harry squint. Maybe this wizard is trying to use Harry's unique connection to Voldemort for some dark ritual. Harry has to use his wits and the few spells he can manage while squinting to try and escape.