I'm with Linda/Lj - you really should go to the vet.
For example, just fyi, when dogs get ringworm - it's notorious for showing up on the top of their heads -- and it doesn't always look like a classic ring like in humans. It can look like a red spot, a blotchy spot, a hairloss spot, a sore, an irritation. Ringworm is VERY contagious to humans and other dogs btw. Puppies are esp vulnerable to getting it.
It could be so many things, when it comes to skin - so I'd go in ASAP and get a skin scraping of the area. Please keep us posted!
