Her other friends, like Ginny or Neville, would also rally around her. Ginny might give her some tough - love advice, telling her to pull herself together while also showing her empathy. Neville would likely offer her some plants he's been growing in the Hogwarts greenhouse, as he believes in the healing power of nature. Together, they'd all form a support system for Hermione during her difficult time.
Harry would probably be very concerned and protective. He's been through a lot himself, and he'd want to be there for Hermione. He might try to comfort her by just sitting with her quietly, sharing his own experiences of tough times to let her know she's not alone.
Harry might be a bit surprised at first. But then he'd understand that it's just another way Hermione is expressing herself. He'd probably be more interested in the meaning behind the tattoos.
She might initially be in shock. Hermione is used to relying on her friends, so the betrayal would be a huge blow. She could then become angry and start to isolate herself. In some fanfictions, she might try to figure out why they did it on her own, using her intelligence to uncover the truth.
Harry and Ron would probably be very worried. They'd rush to her side immediately. Harry might use his skills to try and find a way to heal her quickly, while Ron would be freaking out a bit but also trying to be helpful.
Harry would be extremely worried and determined to find a cure. He'd probably search every corner of the library and consult all his wizarding contacts. Ron, on the other hand, would be initially in shock but then would try to cheer her up with his clumsy humor.
Harry often tries to be there for her. He might not fully understand her depression at first, but he'll stay by her side, offer a listening ear and try to cheer her up in his own clumsy way, like suggesting they go on an adventure or something.
Some of their friends might think it's a strange situation. Luna could see it as a very interesting and magical development, believing that there must be some deeper, cosmic reason for it. Seamus and Dean might be a bit skeptical at first but would warm up to the idea as they see Harry and Hermione making the best of the situation. The Weasley family as a whole would probably have a mix of reactions, from Molly's motherly concern to Fred and George's attempts to find the humor in it.
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.
The Weasley family would be divided. Molly would be heartbroken as she always saw Hermione as part of the family. Some of the Weasley siblings might side with Ron out of loyalty, while others might understand Hermione's point of view. Ginny, for example, might be more empathetic towards Hermione as a fellow woman who has her own ambitions.