school nurse; school health teacher
Refers to the teacher or staff member who works in the school infirmary (保健室), providing health care and health education. In Japanese schools, this person is a licensed teacher with nursing qualifications.
I got injured, so the school nurse treated my wound.
保健室の先生は、生徒の健康相談にのってくれる。
The school nurse gives health advice to students.
Compound of 保健室 (school infirmary) + の (possessive particle) + 先生 (teacher). Literally 'teacher of the infirmary', reflecting the dual role of educator and health professional.