The ornamental design for a brushhead, as shown and described.
FIG. 1 is a front, left side perspective view of the brush head of my design showing different fills on the bristles indicating different color bristles;
FIG. 2 is a front elevation view of the brush head of my design showing different fills on the bristles indicating different color bristles.
FIG. 3 is a rear elevation view of the brush head of my design showing different fills on the bristles indicating different color bristles.
FIG. 4 is a top view of the brush head of my design.
FIG. 5 is a bottom view of the brush head of my design showing different fills on the bristles indicating different color bristles.
FIG. 6 is a right side view of the brush head of my design showing different fills on the bristles indicating different color bristles.
FIG. 7 is a left side view of the brush head of my design showing different fills on the bristles indicating different color bristles; and,
FIG. 8 is an environmental view of the brush head of my design with an extended handle in broken lines and showing different fills on the bristles indicating different color bristles.