About 10 members of the SHG had dragged out Sushama Nayak from her room and assaulted her on Wednesday.
Members of the SHG had locked all the class rooms of the school for about two months alleging mismanagement of school fund, but after intervention of the district administration two rooms were opened on August 21, official sources said.
On Wednesday, the local tehsildar, alongwith police, got rest of the rooms opened.
SHG members suspected that the headmistress might have opened them dragged her out from the room and beat her up.
While Sarojini Patel and Sanjukta Bhainsa, two members of the SHG, were arrested on basis of the FIR lodged by the headmistress, hunt is on to nab the other accused persons, police said.
Both of them were produced before a local court which remanded them to Judicial custody for two weeks.