The ornamental design for a dollhead, as shown and described.
FIG. 1 is a perspective front view of a head portion of a doll showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof; and,
FIG. 5 is a front view thereof similar to FIG. 2 but shown with additional disclaimed structure reflecting a remainder of the doll.
The broken line showing the bottom of the head of the doll represents an unclaimed boundary. The broken line showing of the remainder of the doll in FIG. 5 is for environmental purposes only and forms no part of the claimed design.