The incident also triggered protests against the accused.
Police said that a group of stalkers attacked the victim, a class X student, when she was waiting for her parents along with her friends after a school picnic on Thursday.
The accused allegedly attacked her with a sharp-edged weapon and chopped off her ear.
Before the attack, the accused had allegedly accosted the girl and other students at the picnic.
The victim is undergoing treatment at Sher i Kashmir Institute of Medical Sciences (SKIMS) and needs surgery.
Anantnag SP said police have arrested all those involved. Seven youth were arrested on the complaint of the school principal for eve teasing and injuring a girl student, he said, adding that investigations are on.
The Station House officer of the area has also been suspended.