Alas, it's come back

; I've given Jess the next months dose of Advocate ahead of schedule on the vets advice, I'm washing dog blankets on a fast rota (at least the weather's co-operating and drying them) and I'm hoovering the carpets daily.
I'm wondering what more to do? Johnsons do a dog shampoo with permethrin but washing to dog will wash off the Advocate (according to vet - I wonder now if I should've kept jess dry after the initial application but it's difficult to walk a dog in wales without encountering some damp).
there are also permethrin sprays which I could use on carpets maybe (I don't have cats)?
- permethrin is the only thing I've seen that works on sarcoptic mange and doesn't require a vet prescription which is why I'm looking at it.