His "wound" in the force was an act of self harm (to an extent to save himself), though unintentional.
When all the lives on Malachor V were extinguished by the Mass Shadow Generator and the planet itself died, the Exile heard all the lives being extinguised through the force and couldnt take it anymore. The only way he survived it was defening himself to the force, he couldnt stand the sound so he cut himself off from it (once again he did this by accident, not consciously).
Being near such death must cause serious mental trauma and i can imagine without being able to sense them (as he has been able to since practically a child) made him reclusive and not very eager to "hang out" with them. So to speak.
It is stated he wandered the Rim worls and even travelled beyond Republic space (edge of the known Galaxy).
Since other than the speculation of K3 the only thing i know about that section of space in the Star Wars universe is a species called the Sssiruuk and they definatly wont play a part of this story...
Personally i like to think he just became a traveller... never staying in one place and constantly on the move... in a conversation with Bao Dur you have the option to say that you did what he did after he says he travelled for a while.
Well thats my 2 cents...