Sores on dog's nose.

Dr. Marie-

Our dog has been breaking out in sore/boil/blister type bumps on his muzzle and snout for about a year. They don't develop whiteheads, they aren't filled with pus, they're firm, they cause pain and discomfort. When they first start, the "boils" are smooth and shiny. After a few weeks they become puckered and sort of lumpy. If Loki scratches one of these sores, they bleed a lot, scab, then create an area without fur for a few weeks. If he doesn't scratch them, it takes 4-6 weeks to run its course and to go away. I have a photo:

http://i237.photobucket.com/ablums/ff252/breeligerent/Public/IMAG00221.jpg

We've tried different dog shampoos, antibacterial soaps, flea/tick treatments and anti-worm medicines, and using a moist warm towel compression, but they keep coming back. We don't know if it's a bacterial infection, a dermatological issue, a result of a pest or parasite, or an indication of an immune system issue or internal health problem. We don't know what direction to start in or home remedies to try. We want to take him to the vet, but finances have been really hard for us for a long time. We were hoping for any direction you could lead us in or maybe home remedies that could fix the cause of these sores, but if you think a trip to the vet is the only way to help him, we'll figure out a way to do that.

Thank you for your time,
Breeanne and Azriel