The skullcap is supposed to be inside the head for dynamic hair. That way, the hair looks like it's growing out of the skull. Otherwise, it will be very fake-looking.

The skull showing through is often a problem with dynamic hair. Try increasing the hair density and strand thickness. Another possibility is to add a hair group along the hairline. You can make that high-density, while leaving the rest of the hair low-res.

I guess the ideal would be skullcaps textured for dynamic hair. But I haven't seen any of those.