If your guinea pig has patches of missing skin what should you do?

Answer 1

take it to the vet, it has one of these illnesses Mange

Mange is a common parasitic disease that affects the skin of guinea pigs. This parasite can cause skin irritations and hair loss in large clumps on the back of the guinea pigs. If you suspect your pet is afflicted with mange, it is best to pay a visit to your veterinarian for further examination. While mange is treatable, an illness involving hair loss could indicate further problems, either internal or external. Ringworm Ringworm is a skin parasite that can cause skin irritation and hair loss around the head, neck and nose of the guinea pig. This parasite generally infects young guinea pigs and is transferable from one guinea pig to another and can be transferred from the pet to its owner. Always use caution when handling guinea pigs that you suspect may have contracted ringworm and always wash your hands before and after handling your pet. To treat ringworm, take your guinea pig to your veterinarian -- ringworm is typically treated by either topical or oral medication Lice Lice is a skin parasite that lives by biting and sucking blood from the guinea pig -- they are generally found attached to the hair follicles. Lice can cause sores, hair loss and severe skin irritation and itching. If you suspect your pet has lice, use caution when handling your pet as lice can be transferred from pet to human. Always wash your hands before and after handling your pet. Lice is generally treated by a medicated shampoo. Before beginning treatments, always consult with your veterinarian.