I recently upgraded my IdeaPad with a Wacom tablet attached, to Windows 8.1 along with my graphics driver as well as one other driver.
Following the upgrade my pointer disappeared upon restart. My mouse pointer still appears as normal at the login screen but after I login, it disappears. The cursor is still active, so I can still launch applications but the cursor is not visible and it's incredibly frustrating.
One of the possible reasons shared by a member of our community is that the Pen & Touch option (for Wacom) could have been overwritten or removed as a result of the upgrade.
He shares a workaround which is to reinstall Wacom driver using the CD provided.