Open wound on my three week old puppy?

My puppy has an open wound on the side of his neck which is infected. I have been flushing the infected area with water and putting a damp warm washcloth on it to try and loosen up the puss. I'm wondering if there's anything else I can do to help treat my dog. I don't have the money to take him to the vet right now and need to figure out what I can do until I get the money.