She could also be a bit shocked. In the Hogwarts world, Draco has often been on the opposing side to Hermione. So the fact that he is approaching her to talk about something as personal as her scar might catch her off guard. She may start the conversation tentatively, waiting to see where Draco is going with it, and ready to put up her defenses if necessary.
One possibility is that it represents a shift in their relationship. Maybe Draco has always overlooked Hermione in a way, but seeing the scar makes him view her in a new light, as someone who has been through real challenges and is more complex than he initially thought.
Hermione could also try to reason with Draco. She'll probably start a conversation, trying to understand his motives for capturing her. She might appeal to his better nature if she believes he has one, or try to make him see the error of his ways by using her logical arguments.
He could also be protective. Despite their differences, Draco might have some hidden feelings for Hermione. So, when he sees her scared, he might put aside their past enmity and try to comfort her or keep her safe from whatever is causing her fear. For instance, if there is a threat from another student or a magical creature, Draco could use his Slytherin cunning to protect her.
In some fanfics, Draco's reaction might be complex. At first, he might try to hide his unease or even pretend not to care. But deep down, it could start to eat away at his conscience. He might avoid Hermione for a while because seeing the scar makes him confront the ugliness of the prejudice he has been a part of. However, as the story progresses, this sight could also lead him to gradually change his attitude towards Hermione and those with non - pure - blood status.
Hermione would probably be furious. She's not one to take such an insult lightly. She might immediately retaliate with a scathing comeback, using her intelligence and quick wit to put Lavender in her place.
Hermione may first try to use magic to defend herself or escape right when the kidnapping is taking place. But if that fails, she will start to analyze the situation. She would think about what she knows of Dolohov from her studies and any previous encounters. Then, she would form a plan. She might even try to find allies within Dolohov's ranks if there are any who could be swayed, by appealing to their sense of self - preservation or better nature.
Hermione could also be very hurt. Her hair is part of her identity, and having Draco, who she already has a strained relationship with, do something so cruel would cut deep. She might go to her friends, Harry and Ron, for support. They would likely be just as angry as she is and plot some sort of revenge against Draco and his Slytherin friends.
She might be initially shocked. After all, she would have trusted her friends a great deal. Then she could become very sad and withdrawn. She might throw herself into her studies even more as a way to cope, trying to distract herself from the pain of losing her friends.
After the initial reactions, Hermione may choose to isolate herself for a while to figure things out. She would use this time to study and research, trying to find a solution to the problem with her friends. She might also look for new allies or resources within the fanfiction world to help her deal with the situation.
She might be initially shocked and hurt. Hermione is a character who values her friendships deeply, so their sudden departure would be a big blow. She could spend some time in denial, not believing that they would actually leave her.