Police have registered a case under Sect 21 of the Juvenile Justice Act (care and protection of children) and arrested the boy's mother, police said
The incident occurred at Perumbilli here yesterday.
When the boy failed to go to school on the re-opening day today, one of his neighbours enquired and saw the burn injuries on his stomach, hands and face.
He immediately informed the child welfare committee, who took the child to a hospital.
The boy, a third standard student, is now under the care of the child welfare committee.