During a fight with a Curse you became deaf, and yes, it was permanent, you literally lost your ears.

Well, it could have been worse.

At least they didn't cut you in half.

However, now you can't hear anything. Your classes at the Jujutsu academy continue, because a simple hearing disability will not stop you from becoming a jujutsu sorcerer. You were so deep in thought that you didn't feel Choso grab your shoulder.