Guinea pig first aid help!?

soapy water? i hope you mean proper shampoo..its probably a fungus it starts on guinea pigs faces, so this is probably it. or it could be mites even theres nothing you can than you already have unfortuntley, just try to pre-occupy him from scratching it until you can see a vet. but id defently say its a fungus or mites the only way to get rid of it is by going to the vet, i dont know how he will be over the next 4days so good luck !!