Scabs and losing hair

[Fatnat]

Hi, my sister recently got two more Guinea pigs. Pet shop said bald patch was likely from over grooming but to buy ring worm treatment. She got spray for ring worm and ordered mite treatment too but the bald patches have got bigger. She is waiting to see when the vet can fit them in but just wondering if anyone know what it could be?
Pic with a few red dots is a couple of hours after ring worm spray
Pic of red scan was before she was sprayed.

The other Guinea pig now has a bald patch on its back too so doesn't seem to be over grooming.

Thanks.

 

[Piggies&buns]

Please see a vet and tell her to immediately stop using the treatments. They will not help and could make things much worse.
Plus, using them will hide the evidence a vet needs to make a diagnosis and consequently the wrong diagnosis could be made.

Pet shop products are not strong enough to deal with mites and parasite treatments will not work on ringworm.
Should it be ringworm, then the best treatment is a prescription systemic oral medication, not anything you can buy from a pet shop. Topical creams will not help as spores will continue to be shed from the wider area of infection and continue the cycle of reinfection. Ringworm spores can survive in the environment for up to two years so stringent hygiene is also needed both of the environment personal hygiene. Ringworm will infect a human so you sister needs to wash hands, wear gloves and change clothes etc to help stop the family also catching it.

Guides below contain further information

New Guinea Pig Problems: Sexing & Pregnancy; URI, Ringworm & Parasites; Vet Checks & Customer Rights
Ringworm: Hygiene, Care And Pictures