The ornamental design for a lip gloss applicator, as shown and described.
FIG. 1 is a front elevational view of a lip gloss applicator, embodying our new design the rear elevational view being identical thereto, with the exception of the lip shaped gloss product;
FIG. 2 is a top, front and perspective front of the present invention showing the lip gloss applicator;
FIG. 3 is a left side elevational view of the present invention showing the lip gloss applicator, the right side elevational view being a mirror image thereto; and,
FIG. 4 is a top plan view of the present invention showing the lip gloss applicator.