Since it's a USB mouse, have you tried not plugging it in until you reach the desktop?
Also, is your mouse... cursor(?) actually missing, or is it just invisible? Have you tried moving your mouse in such a way that, if the cursor was there but invisible, it would - for example - cause one of your desktop panels to appear? (The previous makes the assumption that you have set your panels to auto-hide, of course; if you have chosen to keep the default and allow them to eat your desktop's real estate, you'll have to change the setting temporarily.)
Proud to be a Mint user. Running 32-bit Mint 14 Xfce (with Xfce 4.10 and 4.12 PPAs). I have the best modern OS and it runs on my really old hardware, lol.
"Change should never be your goal but, instead, only a means to reach your goal."