§ 820. Unlawful practices. It shall be unlawful for any retailer:

1. to knowingly sell or offer for sale, any drug sold over-the-counter without the need of a prescription, later than the date, if any, marked upon the label as indicative of the date beyond which the contents cannot be expected beyond reasonable doubt to be safe and effective; provided, however, that when such drug is identified as an outdated drug by segregation from regular stock or by other means, the holding of such drug beyond its expiration date shall not be deemed a violation of this section. When the expiration date is expressed by month and year, the expiration date shall be the last day of the month indicated; or

2. to knowingly alter, mutilate, destroy, obliterate or remove by means of a price sticker or otherwise the whole or any part of the expiration date displayed on the label or packaging of any over-the-counter drug.