The little round mark you see on the upper arm is a scar from getting vaccinated against smallpox.
This vaccine was quite common before the 1970s.
It involved using a live virus called Vaccinia to stimulate the immune system and protect against the harmful Variola virus that caused smallpox.
After getting the vaccination, blisters appear at the spot where it was administered, then they dry up and form a crust before eventually healing within a few weeks.
In the end, a circular scar is left behind.
To administer the vaccine, a two-pronged needle was dipped into the Vaccinia solution, and the person’s arm was pricked multiple times.
Every time the needle punctured the skin, a small amount of the vaccine was left behind, leading to the formation of blisters and explaining why the scars are relatively large.
Immediately after receiving the vaccine, there may be a slight swelling at the vaccination site that lasts for about 6-8 hours.
After the initial swelling goes away, the vaccination site returns to its normal appearance. However, after about 6-8 weeks, another swelling occurs, resembling a mosquito bite.
This swelling gradually grows and forms a lump that eventually breaks open, releasing some fluid and forming an ulcer.
The ulcer eventually heals, leaving a scar behind.
This whole process usually takes between 2-5 weeks.
Sometimes, this process of ulceration and healing can happen 2-3 times.
The resulting scar is permanent and lasts a lifetime.
After the early 1970s, smallpox was no longer common in most Western countries, so there was no need for vaccination unless someone was traveling to a country where the virus still existed.