At the beginning of the movie "The Hangover 2," Stu wakes up with a tattoo on his face that's identical to Mike Tyson's.

In fact, the film was almost withheld from theaters when Tyson's tattoo artist sued Warner Brothers, citing design ownership. But they inked a deal, and the movie (tattoos and all) hit theaters in April 2011.

If you're thinking about inking, don't let Tyson's iconic tattoo inspire you.

Tattoo ink is made of a variety of chemicals, almost none of which are approved by the Food and Drug Administration for skin injection. In fact, some inks contain pigments used in printer toner and car paint.

We've warned you before that getting tattooed puts you at risk for chronic infections like hepatitis C. The inks can also trigger a permanent allergic reaction, cause tumors at the site of the tattoo, and invade lymph nodes.

But now, a study published in Scientific Reports that looked into the lymph nodes of four people who had had tattoos found that nanoparticles of tattoo-related chemicals had collected there.

That's concerning, because from the lymph nodes, toxic particles of such a small size can infiltrate all sorts of places in your body and inhibit your immune system.

We don't yet know about long-term damage, but the writing's on the wall, so to speak.

So if you're considering a tattoo, take a moment to contemplate what might happen down the road when your body reacts to the toxic ink infiltrating your organs and tissue.