Writhing Tongue (1980)

Masako, a five-year-old girl living in the suburbs of Chiba, gets a tiny scratch on her finger while playing with mud in a marsh. After that, she suffered all kinds of horrible spasms including biting her tongue. The doctor checks on her for hours on end and arrive at the conclusion that she has tetanus. It seems like the devil has come to dwell in the little girl's body. Her parents have to to bear the sufferings of their child and face the fear that they might also be the victims of tetanus. The once peaceful family has changed completely and the three have been cast into a bottomless hell.