You'll likely just get a letter. You haven't committed an offence until you open and consume the product, at least not one that can be proven. If the police did knock on your door (which I'm pretty certain they won't) plead ignorance.
"Must have been someone who doesn't like me trying to get me in trouble" etc.
There's nothing the police can do, that's why they don't bother with these things. You might get a letter, you might get nothing at all.
Don't get yourself too worked up, it's just a bit of puff. The very worst thing that could happen is a slap on the wrist and a "don't do it again"
You'll be fine.