Am I right to feel a bit weird about this?
Art careers often require a constant, heavy moderation of the gap between subjective sensory perception and objective (commonly perceived or measured) sensory perception. At first the artist may have to force the gap to become fluid. But over time the gap naturally starts to seem very fluid by itself.
The imagination fills in objectively-perceived gaps of missing information very easily, either in terms of imagery or in reasoning/logic.
When I did some casual qualitative interviews with cultist-artists, they were the one group that wanted to believe in their belief systems based mostly on subjective sensory experiences. They were the largest "I've seen things you wouldn't believe" group.
(With respect to the individuals involved; other groups had different perception preferences that would also moderate various issues)
It's easier to draw a parallel outcome that could speak to the above perception, though: I'll venture a bet that this is more a consequence of negative perception of the vaccine by the artists you interacted with; a drop in bleeding during tattooing would manifest in bloodwork as well, and I'd think such bloodwork would show differences in platelet counts, blood concentration, etc. compared to pre-covid samples.
Not an expert; would love an expert opinion on this. But tl;dr: I wouldn't worry about it.
Ironically, he probably can guess who's been vaccinated. So can I. The MAGA hat wearer: zero doses. The one with the stethoscope: triple jab. He attributes this to blood, because he doesn't know what study blinding is. Because he doesn't know anything about science, and yet is putting his judgment over that of people who do.
You are putting your life in this man's hands. He is being forced to follow rules that are designed to protect you from dirty needles, dirty hands, and other causes of death. He is putting his own guesses above those of people who know what they're talking about, and you will never know if that applies to sanitary procedures and other protective measures. I would never allow such a person to touch me.
Also: Women who have not been vaccinated have been having the same heavy and frequent menstruation issues as women who have been vaccinated. I do not know of studies citing this but I have witnessed it firsthand and been told its "been discussed".
There is this: https://www.nichd.nih.gov/newsroom/news/083021-COVID-19-vacc...
from last August