The ornamental design for a foreheadyogamat, as shown and described.
FIG. 1 is a perspective view of the forehead yoga mat of our design;
FIG. 2 is a front elevational view of the forehead yoga mat of our design;
FIG. 3 is a rear elevational view of the forehead yoga mat of our design;
FIG. 4 is a lateral elevational view of the forehead yoga mat of our design, the opposite side view being identical thereto;
FIG. 5 is an end elevational view of the forehead yoga mat of our design, the opposite end view being identical thereto; and,
FIG. 6 is a lateral elevational view of the forehead yoga mat of our design, the mat being shown in an operational environment in which the forehead of a user is resting on the front of the mat.
In the drawings, the broken lines depict environmental subject matter that forms no part of the claimed design.