The ornamental design for a fingershield, as shown and described.
FIG. 1 is a front elevation view of a finger shield according to the present invention.
FIG. 2 is a rear elevation view of the finger shield shown in FIG. 1.
FIG. 3 is a top plan view thereof.
FIG. 4 is a bottom plan view thereof.
FIG. 5 is a right side elevation view thereof.
FIG. 6 is a left side elevation view thereof; and,
FIG. 7 is a front/ right side perspective view thereof. The broken lines, which illustrate how the user would insert their hand into the finger shield, form no part of the claimed design.