Unless the principal transfers to the same midschool, my best advice is that this, too, shall pass. The principal's behavior is very unprofessional.
If you think an airing-out would help things, then by all means ask the principal for a meeting. But make sure you don't "give ground" for the sake of peace. Unless you were out of line, said things you regret, or behaved inappropriately, this is not on you to fix, At the end of the day, dirty looks from the principal are a better burden to bear than not advocating for your child.
But just continue to be polite, professional and courteous. You're volunteering for the sake of your child, and making sure you're helpful to the teacher will prove positive for the relationship that matters the most to your child's daily environment.
There is a teacher that we did battle with when my daughter was in high school. He ended up getting reprimanded over the incident, and to this day he will turn around in an aisle at the grocery store rather than make eye contact. It is HIS problem, because he never accepted the fact that he was in the wrong and hasn't changed, I feel bad he can't move beyond it, but I don't feel bad that I advocated for my daughter when she needed an adult to step in.
