A smallpox vaccine scar is very distinctive, due mostly because the way it is administered.
A nurse or doctor quickly gives the vaccinia vaccine with several punctures on your upper arm. A two-pronged needle is used to direct it into your system. After it is administered, the site of the inoculation is covered with gauze to prevent the virus from spreading to other parts of your body or even another individual.
Over the course of three weeks, the injection site goes through a series of stages very similar to the smallpox rash stages. When this occurs, it is an indication that your body is building immunity to the virus.
To learn more you should go to a medical professional.
Keyword: smallpox vaccine scar