We claim the ornamental design for the derma blade, as shown and described.
FIG. 1 is a front perspective view of a derma blade;
FIG. 2 is a front view of the blade of FIG. 1;
FIG. 3 is a rear view of the blade of FIG. 1;
FIG. 4 is a right side view of the blade of FIG. 1;
FIG. 5 is an left side view of the blade of FIG. 1;
FIG. 6 is a top view of the blade of FIG. 1;
FIG. 7 is a bottom view of the blade of FIG. 1;
FIG. 8 is a bottom perspective of the blade of FIG. 1; and,
FIG. 9 is an environmental perspective view of the blade of FIG. 1.
The broken lines shown in FIGS. 1-9 illustrate portions of the derma blade that form no part of the claimed design. The remaining broken lines shown in FIG. 9 illustrate environment and form no part of the claimed design.