I received a 2016 P dime today. There are no ridges on the side. It is smaller than a regular dime. Has a deep edge on the face side.
Damaged outside of the mint.
@TPG .... Welcome aboard. We will need pictures to conclusively determine what the issue is with your coin. Likely @ErrorsOnCoins is correct... Post Mint Damage (PMD). Cheers, RickO