Legal Question in Criminal Law in Michigan

Ask your local police. Kliszlaw.com

I find this hard to believe. But, if true, you did nothing for your son while this extraordinarily harsh punishment lasted for a full month.

Child protective services may get involved if you report this and you could be very unhappy with the results of their investigation.

This is not criminal child abuse because the teacher's act did not cause physical harm to the child (you didn't say that it did), or did not pose an unreasonable risk of harm or physical injury to the child. Embarrassment is not enough to make it criminal. Complain to the principal or school board, or talk to a civil attorney about any lawsuit options you have. But I don't see a chargeable crime here.