At first, Bakugou may try to act tough and pretend it doesn't bother him. But deep down, it could be eating away at him. He might start to isolate himself more from the class, spending more time alone training. As the bullying continues, he could become more withdrawn and less confident in his abilities, which is a big change for someone as brash as him.
Bakugou could also react in a more strategic way. Instead of immediately getting angry, he might start to gather evidence of the bullying. He could be planning to expose the bullies to the teachers or the school authorities. However, his pride might still get in the way sometimes, and he might struggle with whether to ask for help or handle it all by himself.
Bakugou might react with his usual anger. He could lash out at the bullies verbally or even physically, which might make the situation worse. For example, if someone makes a snide comment, he could respond with a loud and aggressive retort.