Mouse cursor really frequently vanishes
Looks like a someone had this issue as well and accept the answer here : Fix invisible cursor? :


  If your mouse cursor has mysteriously disappeared in OS X, try the
  following tricks in descending order to bring it back:
  
  
  Hit Command+Tab to switch back to the Finder or to another app, then switch back to the active app
  Summon the Force Quit menu by hitting Command+Option+Escape, there is often no need to actually force quit anything as just summoning the
  menu is often enough to make the cursor return
  Quit and relaunch the app, or quit all apps if the cursor is gone everywhere
  Adjust the size of the cursor, found in System Preferences > Accessibility > Display to make it reappear
  
  
  Reboot


Also, he commented that :


  Slightly increasing the cursor size in system preferences seems to have fixed the issue entirely.