My dog has completely torn off his Dew Claw and now has exposed nerve.
My question is do i dress it or leave it for the air to dry it up?
I have bathed it in mild salt solution and put antiseptic wound powder on so far.

Regards  Jonelle

i would get him to the vet asap for stitches and antibiotics

It may need a stitch or two so a vet visit is called for.

My Mum never removed the dewclaws on our boxers when I was a child and I have lasting memories of dogs wearing old socks tied by ribbons until tear wounds healed.

I have a Beardie girl that does this trick!  Oh how I wish they had been removed as a little babe.

She always goes in to the vet and has it tidied up (under sedation), dressed, and antibiotics if the vet thinks she needs them.

I always ask that it be dressed properly, as she's such an ox, she bumps it and screams.  Naturally - exposed nerve ends hurt like the devil.

If it's only the nail that is broken and the skin isn't ripped, then I would have done exactly the same as you.  The nerve will receed very quickly, just as it does when you cut nails.