Articles bought in duty-free shops can be taken on board. But if you fly from Hong Kong to your destination and have to transfer to the next plane, you may need to go through the security check again, which may cause problems.
It is recommended not to unpack the cosmetics and keep the receipt for the next safety inspection. Generally, duty-free shops are behind the security check. Buy cosmetics at the airport duty-free shop. If you fly back to China directly, you don't have to check in.
Extended information: Please don't put restricted items in checked baggage or hand luggage, or carry them with you.
Please do not load flammable liquids, corrosive substances, gas cylinders and other dangerous goods in the checked baggage or hand luggage, because these dangerous goods will pose a threat to the safety of the aircraft. Spare lithium batteries and portable power packs shall not be placed in checked baggage.
All liquids, aerosols and gels in hand luggage should be placed in containers not larger than 100 ml, and packed in transparent plastic bags with a capacity of 1 l or less. Each passenger is allowed to use only one transparent plastic bag. Drugs, baby milk food and special dietary requirements can be exempted, but they must be verified. Any lag that does not meet the above requirements must be dealt with before the safety inspection.
Hand luggage or electronic and metal objects on people should be put in a separate tray for safety inspection.
From August 20 18 13, all transit passengers who use anti-theft sealed plastic bags at the Hong Kong International Airport to travel behind time must use special lag inspection equipment at the transit passenger security checkpoint to strengthen security inspection.
In some cases, labels in sealed plastic bags must be removed from the bags for inspection. After cleaning, LAG will be repackaged in a new tamper-proof sealed plastic bag provided by Hong Kong International Airport.
Source of reference: Hong Kong International Airport-Airport Security.