The owner needs to remove the bedding, cotton wool, bath sand, etc. in the cage immediately. If the weather is very cold, move to an air-conditioned room. (There is no condition to replace all the bedding materials with absorbent cotton). Then dip a cotton swab in saline solution, clean the hamster's eye sockets, and then apply some chlortetracycline eye ointment.
The owner can brew isatis root and give it to the hamster, and he can also feed it some Anti-inflammatory drugs. If the cold is particularly severe, you need to take your hamster to a pet hospital for professional treatment. This is the safest and most reliable way.
The owner here needs to pay attention to the fact that colds are also contagious. If it is a "multi-rat household" and a hamster catches a cold, it must be isolated from healthy hamsters. At the same time, the cage and cage of the cold hamster must be Disinfect daily necessities.