[smartpuppiepets]

To The OP :
If you only have had the puppy for 5 days i would consider working something out with the breeder ASAP . For the consciousness and the dilemma of if she will put the puppy down or not, at this point this is the breeder dilemma, not yours to deal with it.
Yes, you may better off considering an exchange for the same litter while you have the opportunity than risk getting stuck with something that is not your responsibility to deal with. Ask your vet to write a letter right away, deeming the puppy "unfit" for a sale and you will be legally covered if the LS diagnose comes to be true as it is a life threatening condition.
The only thing you need to figure out right now is if this may be possibly a reaction to the Sentinel , than you would be unfair to the breeder , since it is too much of a coincidence that the puppy was fine until you gave him this and next day he shows up with this symptom. Your problem made me realize why some breeders will void any and all guarantees on any puppy given anything withing the first 10 days of arrival to new home.
Anyways, i hope it is good news for both of you and the breeder as well. It sounds like an accident, nothing irresponsibly caused .
But no matter what it is, if it is a condition the puppy has been born with, you are not responsible having the puppy only for 5 days .
But if it a sentinel reaction i am sure you will do the right thing and take full responsibility for it .
Blessings.
XOXO