The period-after-opening symbol or PAO symbol is a graphic symbol that identifies the useful lifetime of a cosmetic product after its package has been opened for the first time. It depicts an open cosmetics pot and is used together with a written number of months or years

This is the case with many skincare and cosmetics as they are able to be used within a certain amount of time after opening, 

This is shown by a symbol on the packaging - Image result for pao symbol with the indicated amount of months you have to use the product.

Batch codes are just and indication of when the batch was started and is not an indication of an expire date, Unless clearly stated on the packaging.

In the event that a date is shown on the package, this will either refer to the manufacturing or expiry date.

If the product shows an expiry date, it will look like either EXP 01/01/2023 or 01/01/2019 EXP. It will clearly state 'EXP' or 'Expires'.

If a date is shown like '01/01/2019' or  '01/01/2019 A (usually followed by a letter reference)', this will refer to the manufacturing date - the date on which the product was created.