You "heard," eh? It's nice to know that, even in the Internet Age, some folks are still getting their medical knowledge from the rumor mill. ("Sure, I'm a doctor—but not one of your fancy, book-learning doctors! I picked up otolaryngological surgery the old-fashioned way—on the streets.")
Your credentials from the Medical School of Hard Knocks notwithstanding, your question is a reasonable one. Unfortunately, the answer requires some technical detail.
Since I'm aware that many Americans fall into a deep coma when exposed to even a small amount of undiluted science, I will try to present this detail in such a fashion as to keep everyone with me. Ready?
Human skin—such as that found on a pair of ripe, firm breasts—is composed of two layers. The cells of the outer layer, or epidermis, do indeed regenerate, working their way up to the naked, heaving surface over the course of about a month.
Then these dissipated, wanton epidermal cells are sloughed off, in a manner you might observe if you were rubbing a loofah on the soapy, chiseled body of Channing Tatum.
However, the underlying layer, or dermis, doesn't participate in this process. Provided the tattooist can get her pigments just below the epidermis, scarlike fibroblasts will coalesce around them and make them more or less permanent.
That's "more or less," not "totally." Since your favorite waitress is probably 19 (you animal), I'm sure her tats look fine. Over decades, though, they'll spread out as the fibroblasts migrate ever deeper into the body. If you live long enough for your tattoo pigments to reach your heart, it's said you'll turn into Lemmy from Motörhead.
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