My dogs head has red soares on it?

I know I have been asking alot of questions about my dog and I am working on scheduling a vet visit (ASAP now) he has been getting tiny soars or bumps on his legs and headd, at first i thought it was heat soars or whatever they call them, then i thought maybefleas. I see no fleas and I do have medicine on him for them. I think thought it was an allergic reaction to the wet food I wass giving him. I stopped the wet food and on his legs it seemed to clear up. He has very little fur since he is part pit, however on his head, there is a scab and i gave him a bath tonight and it seems to have gotten worse on his head! I dont think its an allergic reaction to the shampoo since this was happening prior to using the shampoo. here is a photo of what it looks like. It actually looks worse in the photo then it does in person, but I thought maybe one of you might have an idea of what it is.
http://lyonsdesign.info/photo.jpg
http://lyonsdesign.info/photo(2).jpg