This is a touchy subject and each PM Dr may have different policy. My PM Dr doesn't like me to be over or under. However we don't have to bring anything in thankfully.
He says if you have extra just let me know so I can adjust the quantity on your next script. I think he's more worried about people running short since most people would be in trouble those days without meds.
As for the OP, you bought them so keep them. However tell him to write the next script with 15-20 less.