This might be a fungal infection or a bacterial infection and could be a reaction to an insect bite or sting.
unfortunately only one picture got linked in and that one is so large as to be out of focus.
But you can read here about lumps on dogs including some around the nose
http://www.peteducation.com/article.cfm?c=2&aid=424
You are right a vet visit is the best bet.
Tonight you can try cleaning the area with betadine iodine solution if you have it on hand and its safe to use Neosporin or Triple Antibiotic ointment on the spot as it won't hurt the dog if he licks that.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics