Surface Pen

So I replaced my battery with one from a few months ago, I remember putting the + side outside My pen is the 2017 version When I pressed the eraser for 7 seconds it didn't light up and it didn't show up in the list of devices (It's a surface pro 5) What do I do?

Hi I have a surrface Pro 4. I haven't use the pen in a while but I use it once a month or so to make sure it works. So I was checking to see if all functions worked today and when i clicked on top to open OneNote it did not open. So I went onto youtube and unpaired and repaired it. The pen...