If your dog has dark nails and you can't see the quick, I recommend just taking off the pointed end of the nail for now. (topdogtips.com)
If it is the wrong size, you can sometimes trim the open end of the nail cap to adjust it. (softpaws.com)
If it doesn't fit, trim the open end of each nail cap until they fit your dog's claws snugly OR, before altering the nail caps, send the complete package back for an exchange. (softpaws.com)