“Ring worm” is really just a fungal infection. It’s got nothing to do with any worm infestation. Fungal infection of the skin typically (but not always) appears in a near-circular fashion (thus “ring”). The source of infection may be from another human (usually a family member) or animal (most commonly the family cat or guinea pig).
This lady’s rash on the face appeared soon after she adopted her ex-neighbour’s cat.