Fixing this problem is rather too easy. Open a terminal (Ctrl+Alt+T) and use the following command:
gsettings set org.gnome.settings-daemon.plugins.cursor active false
You’ll have to work a bit to copy this command with an invisible cursor. I leave that to you As soon as this command is applied, cursor will be visible again like it should have been. No need for a restart.
I hope this quick tip helps you to fix invisible cursor problem in Ubuntu 13.10. Questions, suggestions are always welcomed. Enjoy