The family of a Bronx boy serving time in a juvenile rehabilitation facility plans to sue the facility and state after the boy was allegedly severely beaten.

Jamie Beltran, 16, was serving a three-month sentence for a misdemeanor crime at a state-run Children and Family Services Center when he claims a fellow resident attacked and left him with lifelong injuries.

"Metal plate in my head," Beltran said. "Left side of my head is numb, and doctor say it may be numb for the rest of my life."

According to Beltran's lawyer, the security guard in the classroom broke protocol by leaving for a bathroom break without being relieved. The guard said staffing shortages made him break the policy and leave the classroom unsupervised. The facility denied a staffing problem and suspended the guard.

Beltran's lawyer said the family will file its claim against the state and the facility this week.