Bulldog is shedding and blisterring?

I have an 11month old bulldog. He has been shedding for about month and a half really badly. And he keeps getting like scabs on his skin. They start like reddish then become scabs and it all continues. im wonderring if anyone knows what it might be?the redish blisters arnt just on one spot they will move around, but mainly around his neck. He wears no collar, he is not in the sun, dirt, or anything of that type. Changed his food to solid cold to make sure its not allergies, and he doesn't bite himself. He's indoors. And isn't around any chemicals. I shower him every so offtern. They start going away then just reappear