Help I pooped my pants :))))?

I say you should just laugh and get over it, you can't do anything now, people will start joking about you and you should joke about it too, they will try and tease you. If you make fun of yourself, they won't see a reason to do it so that should help reduce the amount of embarrassment. And you could tell the principle that the teacher wouldn't let you go to the bathroom and you had no other choice, not your fault at all and if you get punished for it, that means your school is being run by morons and should be closed. This was all the teacher's fault.