It seems reasonably straightforward. Use the Polyextrude to scale down and then inset an extrusion or two, then scale down and pull up the horn. I've attached a simple example. Keep the Polyextrudes set to “local control” and you can do both main horns simultaneously.
Generally I would suggest you are adding too much detail too early with your head. You'll be adding in specific details later with polysplit and edgeloops, so keep the head much simpler at this stage.