Most likely not. In the world of wrestling, there are often unfounded rumors. Rey Mysterio is a well - respected figure, and such a demeaning story is probably baseless.
There's not enough information provided to really define what this 'little ballerina hina bitch story' entails. It might be a fictional narrative created by an individual. Maybe 'hina' is a character who is a ballerina, but without more context, it's difficult to say more. For example, it could be a story about a ballerina named Hina who faces some sort of challenges in her dancing career or personal life, but that's just speculation.
Once upon a time at a party, there was a boy who was acting in a rather annoying way. People started calling him 'little bitch boy' because he was constantly whining and trying to get all the attention. He would run around and knock over drinks. No one really wanted to be around him, but he didn't seem to notice. He just continued his unruly behavior until finally, the host had to ask him to leave.
Perhaps this is a very niche or local story. Rey Mysterio has a huge fan base around the world. He has entertained millions with his lucha libre style. It's possible that this 'story' is something fabricated by a small group who may have some sort of grudge or just trying to create controversy, but there's no evidence of any legitimate negative story that is common knowledge.
Given the name of the story, it would seem that Hina, the ballerina, is likely to be a central character. However, without further information about the story, we can't be certain if there are other important characters. There could be a teacher, a rival ballerina, or a family member that also plays a significant role in the story.
One reason could be that he's just a spoiled brat. Maybe he's used to getting his way at home and doesn't know how to act in a social setting like a party. Another possibility is that he's really insecure and acts out to get attention, even if it's negative attention.
Since there's no common knowledge about a story named exactly like that, it might be a very private or unique story created by someone. Maybe it's about an experience related to the feet, perhaps a strange or funny encounter involving the area between the toes, but without more context, it's hard to say for sure.
I would recommend 'The Unlikely Bond' which beautifully portrays the growth of Akko and Diana's relationship. It starts with them as rivals in school and gradually shows how they come to understand and care for each other.
One great 'Little Witch Academia' fanfiction is 'A New Adventure at Luna Nova'. It continues the story of Akko and her friends with new magical challenges. The characters are well - written and it stays true to the spirit of the original series.