It's not a common name. Piispa always has something to do with the church. It either means pastor or church.
The Piispanens in Finland that I've researched were well educated even in the 1600s, studying in both Helsinki and Uppsala in Sweden. I really encourage you to look up Simon Marci Krook. Someone must have taken a long time to create such a detailed record. When I stumbled on it I was surprised to see my grandmothers name and her birth and death dates even though she died in the US.
My grandmothers female line goes to Laapajarvi with names like Pynttari and Skrabb. Here most distant direct ancestress was Malin Mansdotter.
Enjoy your Krook research and who knows, you may find your Piispanens in there too!