Tbh, I'd treat it like a wound you had yourself. Get some antiseptic spay after you've flushed it out properly.
Savlon healing gel (not the cream, it's slower to work) clean and reapply twice a day, don't see the need for vets, vets would charge you £80+
If your gonna be working the dog you need to be able to do the basics.
Hope the dog is ok ?
Cheers, D.