The ornamental design for a massager accessory, as shown and described.
FIG. 1 is a first perspective view of a massager accessory showing my new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof; and,
FIG. 9 is a perspective view of the using state of the massager accessory thereof.
Massager accessory is shown with a symbolic break in its height. The appearance of any portion of the article between the break lines forms no part of the design. The short dash broken lines shown in the drawings represent boundaries of the massager accessory that form no part of the claimed design. The long dash broken lines show environmental subject matter of the claim in use and form no part of the claimed design.