Pen stopped working

Last night, my pen stopped working. I thought it was my computer, but the mouse actually works fine on my tablet. I cannot click on anything on my tablet. Does anyone have a quick fix?

Is the pen working in any other software?

You say the mouse worked on your tablet, is this a mouse that comes with the tablet?

What brand is the tablet?

What tablet do you have. and is it a pen display or just a pen tablet? and when you say mouse do you mean actual mouse and mouse cursor or finger touch and mouse cursor?
I assume it is a pen display. I need to know if it has touch functionality and if that works. Also need to know if this happens randomly after a reboot or if it is like this all the time.