I think we talked about this on another thread.

Yes, I have run without toenails.  Probably all of us have at one time or another.  Heck, it takes months to grow in new nails so I wouldn't stop running for that.  But I will say that I never lost the big toenail, that might be a little different.  I have a longer second toe (Morton's toe) so I lose that nail all the time - no biggie.

Over the years I've lost a toenail or two training and running.  I find the initial pain is from the blister under the nail be it a water or blood blister (black nail).  For me, I just cut the toe nail back a bit and try to let the pressure (water or blood) out.  Some folks do this with a steralized needle.  Once the pressure is gone, the toe feels much better. The nail is dead.  You can cut it off or have it removed.  Doctors frown on us "do it yourselfers".  However, once it's removed it's fine.  I'll be running the next morning.  Keep it clean.  I use antibiotic cream on it for a bit of protection and keep an eye on it so it doesn't get infected.  Like I said in another post, I'm running with 9 toenails even as we speak.

I seem to always lose me big toenail. I put tape around the toe don't really hurt the much when i run.

I found that Patrolium Jelly on the toes prevents blisters from forming under the nails. Since applicating to my toes and other "hot spots" I have very few blisters. I run anywhere from 25-50 miles per week, depending on what I am training for. 

Watch this weekend I get a nasty blood blister. LOL.