Tonton Streaming Monsters (1988) S1E1 - The Feverman

When a doctor is unable to heal a man's sick daughter, the desperate father goes to a 'Feverman', a mysterious healer who literally fights the illness by summoning a physical manifestation of it from within the patient. The doctor, angry at the father's belief in superstition, tries to expose the Feverman as a fraud. In doing so, not only does he learn the truth, but there's also a price to pay for faith.