I found my teachers facebook
Were you looking for your teacher's Facebook?
I'm going to post my grades on his facebook.
You should not try to contact teachers outside of school hours. It can come off a little stalkerish, and I know you are not that type of person.
It's fine I don't care about your opinion.
When you do this it will be public and everyone's opinion will matter. Please talk to your teacher in private about your grades.