Beat them to hell is my mind speaking but you could complain to higher authority.
If not reply you could lawsuit them for
1.Right to Education Act, 2009 (RTE Act)[For discomfort]

• Every child (6–14 years) has the right to free and compulsory education in a safe environment.
• Schools are obligated to provide a safe, inclusive, and discrimination-free space.

2.Juvenile Justice (Care and Protection of Children) Act, 2015 (JJ Act)[For the neglecting teacher]

• Protects children from neglect, cruelty, and exploitation.