It's one of Newton's Laws of Physics, "A body that is stupid will remain stupid..."

had this happen to me as a teenager, the teacher yelled at me in front of the whole class lol it sucks.

had a math teacher call me an idiot for giving her the wrong answer to a question. not the numerical wrong answer, just not worded the same way as the book explained it. some teachers just aren't good. be it at people skills, presenting information, or sometimes being good people. but fight through the urge to swing and graduate... then you are free of school. not free to live a life of happiness... but free of school.

It was crappy of her to call you out in front of the class like that, but how badly did you mess up if she felt the need to say something right away?