Reply To: When I use the grease pen, it cuts away a part of the object, but it also creates a really long set of faces extending out…

[Kent Trammell]

The same thing does happen to me on occasion. It’s a sign that the tool failed to complete its operation – only a partial success. I’m not sure how to fix it aside from trying it again till it succeeds.

I fear the developer of the addon doesn’t maintain it anymore, but you can submit bugs/issues to his github page: https://github.com/MadMinstrel/blender-sculpt-tools/issues