Remember that the South would still be a very divided place. The divide between poor and rich whites would only get worse and I can see conflict with Huey Long and friends against the traditional state governments dominated by the wealthy elites. Blacks could also use the civil war to attempt to break free from their oppressors, possibly aligning with Long.
In regards to Fascism in America think less Hitler and more of Huey Long's Louisiana in terms of state control. White supremacy would see a revival in the South if whites start feeling threatened by the black population but it wouldn't rise to concentration camps.
It's important to note that states would be just as divided as the country at large and miniature civil wars and rebellions wouldn't be out of the question especially in larger ones. Another thing to consider is the American military. Would it be neutral, would it fracture along different lines, or would they attempt to restore order in certain regions. I suppose that is up to you but hopefully I have given some useful insight for your timeline.🙂