Bad taste in mouth after wisdom teeth removal. Normal?

I got my wisdom teeth removed (all four) 7 days ago. I had a followup appointment yesterday with my oral surgeon, he said everything was healing normally and gave me the syringe to flush out food particles and whatnot. This morning out of nowhere there is this really strange taste in my mouth, kinda sour and metallic. I used the syringe to flush out the holes in my mouth and a little food came out but the taste is still lingering. There is no pain so I don't suspect dry socket (well I really hope not), but if it was an infection wouldn't have he seen it yesterday when he was looking at my teeth? Or is this all a normal part of healing? Its disgusting so I just would like to know how long its going to last.