Sounds like ringworm, which is not a worm at all. Be careful, you can catch it from her, and spread it too. Here is an article I found: This is an uncommon condition in the pig but where it does exist it is of little economic significance. However it is a condition that can be transmitted to the human. It is caused by a dematophyte fungus. Unlike other animals there is no specific host-adapted species. Trichophyton and Microsporum species are involved. Infected skin shows gradually increasing circular areas of light to dark brown discoloration behind the ears and on the back and flanks.
Infection can occur in all classes of stock. The fungi enter the skin through abrasions and diagnosis is made by examining scrapings from suspicious areas under the microscope to look for fungal spores. Treatment consists of washing the area with 1% savlon or hexetadene skin disinfectants or fungicides. In cases where infection is widespread, which would be rare, the pig can be treated orally with griseofulvin antibiotic at a level of 10mg/kg for a period of 7 days