Well, she could turn into a more remorseful person. After cheating on Naruto, she would likely be filled with regret. This might lead to her trying to make amends in various ways. For example, she might start doing small things to help Naruto from afar without him knowing, like leaving him useful items or helping to solve problems that affect him indirectly. She'll be haunted by her actions and constantly strive to be a better person.
She might become more self - loathing. Since Hinata has always been portrayed as someone who deeply loves Naruto, cheating goes against her core values. This act could make her question her own morality and self - worth. She may become withdrawn and less confident in her relationships, constantly fearing that others will discover her misdeed.
Hinata may change in terms of her relationship with others too. Her friends and family, if they find out, would be disappointed. She might lose some of their trust. In the fanfiction world, this could isolate her. But at the same time, this isolation might be a chance for her to really reflect on what she's done. She could become more independent in her self - discovery journey of trying to understand why she made such a mistake and how to fix it.