Updated

Children's Hospital of Orange County says a child received surgery on the wrong body part this week but no permanent harm was done.

The mistake is the third of its kind in four years and state regulators are investigating.

A hospital statement says one of its surgeons on Tuesday was supposed to loosen a fold of tissue behind the child's upper lip but instead loosened tissue under the tongue.

The intended procedure was also performed and the child was sent home.

The hospital says the outpatient procedure won't cause any long-term harm and it regrets the mistake.

In 2006, a Children's Hospital surgeon cut into the wrong side of the skull during brain surgery. In 2007, tubes were inserted into both of a child's ears instead of one.

Both mistakes were corrected.