He promised his sister or mom that he wouldn't fight anymore, and the last time he fought, he either accidently beat up his best friend or pissed off enough others that they beat up his best friend and he lost his friend because of it, as well as getting suspended. So he thought it better to just let them beat him up thinking it would sate their "bloodlust" so to speak, and they would then leave his new friend (handkerchief) alone.
Why act beaten up
He promised his sister or mom that he wouldn't fight anymore, and the last time he fought, he either accidently beat up his best friend or pissed off enough others that they beat up his best friend and he lost his friend because of it, as well as getting suspended. So he thought it better to just let them beat him up thinking it would sate their "bloodlust" so to speak, and they would then leave his new friend (handkerchief) alone.