Police arrested Collier on two counts of assault and battery, The Huffington Post reported Friday, and all three of her children were placed into protective custody.
The child she accidentally slapped had come to the principal's office feeling sick and was waiting for his own mom to pick him up.
Spartanburg County Sheriff Lt. Tony Ivey offered some anger-management advice to Collier and other parents with hot tempers:
"I'd try to control your emotions a little bit when it comes to children and especially in public atmospheres here," he told WYFF 4 News. "Sometimes it's better to count to 10 or go off and cool off for a little bit, then go back with a level head before you start to discipline your children."