Unlikely. At most dispensaries I've been to, if they accidentally drop a bud on the counter while filling the container they have to toss it, they can't just put it into your jar, or back in the container to sell to someone else.

And edibles are technically food product; you can't returned opened food to the supermarket, unless it's literally defective.

Try eating just a half, or even a quarter. You don't have to eat the whole thing, and many edibles are formed / molded precisely for this purpose.