FIG. 1 is a top perspective view of my new design for a comb straightener. FIG. 2 is a top plan view of FIG. 1. FIG. 3 is a bottom plan view of FIG. 1. FIG. 4 is a front side elevation view of FIG. 1 FIG. 5 is a rear side elevation view of FIG. 1. FIG. 6 is a right side elevation view of FIG. 1; and, FIG. 7 is a left side elevation view of FIG. 1.