Vets don't have to know exactly what caused something, to treat a infection.
I keep miconahex + triz spray, and also keep vetericyn on hand. I use it on scrapes, cuts, bumps. Or anything that dogs want to lick, and could become infected.
I still take my dogs to the vet, if it does not improve, or becomes worse.
The things above can be used, along with your vets antibiotics. And absolutely nothing wrong with soaking the dog's feet in a Epson salt bath.
Not all those who wander are lost.
Life is just a leap of faith.
Spread your arms and hold your breath and always trust your cape.
Two things define you. Your patience when you have nothing, and your attitude when you have everything.