When a student is hit in the face by a teacher, it is unacceptable behavior and needs to be properly handled. Parents should first keep calm, but we can't ignore this problem. They should contact the school immediately, report the incident to the school management or relevant departments, and ask for investigation and take appropriate corrective measures. Moreover, parents can collect relevant evidence, such as students' oral descriptions, photos or videos, to support their claims. If the school fails to solve the problem properly, parents can consider complaining to the education authorities or relevant institutions to seek further support and intervention.