I don't think it's unusual for a vet to miss a dew claw or two especially if they are doing 5 puppies as he was with gracie.
Dew claw removal must be done under anethesia, according to my vet if the puppy is more than a week old. If one is missed, it is generally done during spaying or neutering (why put them under more than necessary) or if another surgery is being performed.
Dew claws are a pain while grooming, and gracie was forever getting hers hung in blankets, grass, twigs, etc., so it was only a question of WHEN to do it for me.
She did lick at the dressing for several days, never licked her abdominal incision but twice that I know of, but I would keep her distracted as much as possible, bitter apple spray can be applied.
Gracie is much happier dew-less, and so am I AND the groomer........
Also, you may want to check on the laser surgery for Schatzie, it does cost more, but I got a bought a coupon for a free spay from a local animal league, check with your vet to see which coupons your vet will honor, and so the cost of the laser addition was virtually defrayed. I also opted for morphine for pain..........it really helped get gracie AND ME through the first night more at ease..............hope this helps!!!
Di and Gracie