When it comes to things like Orf when the vets say "its a virus mate" everyone wants antibiotics/snake oil/homeopathy/witchcraft and damn the price!
If it is secondarily infected it is despite the sulphur, antibiotic spray and Alamycin which has already been thrown at it. Can we say officially now on TAS that antibiotics do not cure Orf and save people the expense, the animals the stress of handling and injecting and the increased risk of antibiotic resistance?

Probably, the disease has done its worst by now and it will begin the healing process. Your vet would be an ideal person to talk to, most don't charge for phone advice

A piss up is probably your best option equally effective, more enjoyable..