It is usually spread when a person touches a cold sore or touches
infected fluid-such as from sharing eating utensils or razors, kissing an
infected person, or touching that person's saliva.
The skin around the blisters is often red, swollen, and sore. The blisters may break open, leak a clear fluid, and then scab over after a few days. They usually heal after several days to 2 weeks. Small children sometimes drool before cold sores appear. This fits in with what you have described.