Damaged hard drive due to magnet damage (Macbook Pro) I am able to get internet recovery on my Macbook Pro that I previously wiped with a magnet

I was trying to re-install OS X Mountain Lion again but when I got to the 'choose a disk' there was no 'disk' to be found. 

I'm not too sure what this means, could someone please explain if this is something I can fix myself?
The HDD work using a magnetic head to read and write,.

The disk it self is coated with magnetic material. So your Magnet has changed the information stored (damage), but possibly not permanent.

So your best choice it to completely reformat the disk, then install a OS.