Are you asking if the teachers physical contact and abuse of your son could lead to the possibility of a damages claim against the teacher and/or the school? If so, there are many possible scenarios which could affect the nature of the claim, including, if the school was private of public. You would be best served to consult with a local attorney as there are potential notice deadlines should you choose to pursue a claim.
My colleagues are way off base, what you describe is criminal child abuse. Call the cops and CPS. No one including you should smack a child in the face with a foreign object.
This is not legal advice but a general comment on society.