The state Medical Examining Board disciplined four doctors on Tuesday, including reprimanding and fining a prominent Norwalk plastic surgeon $2,500 for failing to keep adequate medical records. The medical license of the plastic surgeon, Dr. Laurence Kirwan, was also placed on probation for four months while he must complete a course in medical documentation, a consent order states. In 2015, the mother of a patient who had two chin procedures from Kirwan in 2014 filed a complaint with the state Department of Public Health, records show. A plastic surgery consultant found that Kirwan’s treatment records did not meet the standard of care, records show. On his blog, Kirwan says he is a professor and an internationally recognized expert in plastic surgery who has practiced in Norwalk, Manhattan and London.