The ornamental design for a wax warmer, as shown and described.
FIG. 1 is a front and top perspective view of a wax warmer, showing my design.
FIG. 2 is a front and bottom perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a left side elevation view thereof.
FIG. 6 is a right side elevation view thereof.
FIG. 7 is a top plan view thereof.
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a perspective view of the of the wax warmer of FIG. 1 wherein a cover of the wax warmer is open and an inner container of the wax warmer is taken out from the wax warmer.