It's hard to say based on the picture. Do you mean that the skin on his back is spotted, as in he has black skin with white spots? Or is all of his skin black, with some brown/black quills and some white quills? If the spots are on his skin, that makes him a pinto, whereas if the spots you're describing are just white quills, that means your baby has some snowflaking.
We'd be able to tell you more if we had a clear shot of his face.
We'd be able to tell you more if we had a clear shot of his face.