When your child has cold sores, or fever blisters, you can expect to see:
The herpes simplex virus causes cold sores. The sores happen the first time after getting it from someone who has herpes. After the first time, the virus lives inside the nerves of the skin. A few people get the cold sores again and again. The cold sores could come back because of things like being cold, tired, or stressed, or having a sunburn or fever.
Here's what you can do if your child gets cold sores: