My mouse cursor won't appear on the pause menu screens.

Sorry to hear that you are having issues @PrettyUncreative.

There's a couple of things to try when an issue such as this pops up: 

Can you open control panel -> Mouse -> Pointer Options -> deselect any boxes that are checked including Enhance Pointer Precision.

Do you have any USB devices such as a controller plugged in, if so can you unplug them and then try again to see if the issue is still there.

Now this may sound like an odd one but at times this issue can be caused if you have a standalone GPU alongside an integrated card.  

If this is the case then you can change from your integrated card to your Nvidia card for example by following the steps below:

• Open "Nvidia Control Panel".
• Select "Manage 3D Settings" under 3D Settings.
• Click on "Program Settings" tab and then select the program you want to run.
• Select "Preferred graphics processor" in drop-down menu and then select use the dedicated graphics card, select High-performance Nvidia processor.

Let me know how you get on.

Darko