What is claimed is the ornamental design for a neck warmer, as shown and described.
FIG. 1 is a perspective view of a neck warmer, showing the new design in a worn position;
FIG. 2 is a front elevational view thereof in a flat position;
FIG. 3 is a top plan view of FIG. 2;
FIG. 4 is a bottom plan view of FIG. 2;
FIG. 5 is a rear elevational view of FIG. 2;
FIG. 6 is a right-side elevational view of FIG. 2; and,
FIG. 7 is a left-side elevational view of FIG. 2.
The broken lines showing a person in FIG. 1 are included for the purpose of illustrating the invention in use, and form no part of the claimed design. The strings shown in FIGS. 2-5 include break lines to denote indeterminate length and for clarity of illustration.