The ornamental design for a part for a handheldmassager, as shown and described.
FIG. 1 is a perspective view of a part for a handheld massager;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof with the part for a handheld massager oriented upside down.
The broken lines shown in the drawings are for the purpose of illustrating portions of the part for a handheld massager, which form no part of the claimed design.