Regulations are left to the individual States. Some have no regulations, others allow it with parental consent, others don't allow it at all if you're a minor.Is that a thing in the US?
Dylan's first three tattoo's where probably without parental consent when he was 16 and 17.
He did the 1st himself, a stick and poke.
The 2nd and 3rd, including the triangle on his chest, were when he was 17 and was done by an ex-con who he bumped into and did it privately.
And these laws would be for licensed locations. If someone underage did it outside of a licensed business, don't know how the laws would apply. I would assume they still would.