We claim the ornamental design for a handheld electronic device skin, as shown and described.
FIG. 1 is a back left perspective view of a handheld electronic device skin;
FIG. 2 is a back elevational view of the handheld electronic device skin;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a right elevational view thereof;
FIG. 5 is a left elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a back right perspective view thereof.
In the drawing, the broken lines depict unclaimed portions of the handheld electronic device skin. The broken lines form no part of the claimed design.