Please see a vet for ringworm during regular opening hours and follow our ringworm hygiene tips for home care to make sure that you prevent transmission and re-infection. After a decade we have worked out about every possible angle of transmission and have found a way to address it; that is why it is worth following the advice and getting on top of it once and for all.
Do not accept just anti-fungal cream as treatment; it does not reach the full infected area that still has got hairs and does not prevent any spores from spreading and causing more infected patches that have to run their own due course. if you can, please ask your vet for a prescription-only oral medication as the least stressful and most effective way to treat. A round of fungicidal dips or shampoos is the next best alternative.
Ringworm is the single most common transmittable problem between humans and other pet species. Ringworm spores are invisibly tiny and very long lived; which is why so many shops (and for sale breeders) struggle.
What to check and look out for in new guinea pigs (vet checks, sexing, parasites&illness) (including tips on how to reclaim vet cost in newly bought guinea pigs)
Ringworm: Hygiene And Pictures (although includes advice on human prevention and care)