Yesterday, I made the mistake of killing Benny in the Tops without the assistance of Swank. As a result, every time I enter the Tops a shootout occurs. This is unfortunate considering I haven't completed the "Talent Pool" quest. Even the characters associated with the quest become hostile. Is there a cooling off period with a faction or location, like there was in FO3? For example, if you got Rivet City made, all you had to do was stay away for 3 days and they would forgive. Thanks in advance guys and girls!

I'm not 100% sure about this, but i think that there is a cool off period. why dont you try coming back later?
Try waiting a few days, then travel around the wasteland abit, i THINK it all just blows over, and if you save, then what have you got to lose anyways?

There is no cooloff period. You're out of luck on that quest.