I had the same thing happen to a horsecollar BC. Same material and tear type, too much unraveling to sew back. The problem with a sew job is you'll need to gather the material in more and it'll be a very noticeable blem; that and most home needles will poke "big" holes which the material will just unravel and tear at again.
If warranty doesn't cover it I would use Aqua Seal. Take out the bladder and seal the inside of the outer cover, it'll keep the blem looking better. Wear gloves and work on a large sheet of wax paper, otherwise you'll regret the cleanup.
If warranty doesn't cover it I would use Aqua Seal. Take out the bladder and seal the inside of the outer cover, it'll keep the blem looking better. Wear gloves and work on a large sheet of wax paper, otherwise you'll regret the cleanup.