tattoo is a form of body modification.
'ink permanently implanted under the skin
Tattooing is a process by which pigment (ink) is permanently deposited (implanted) under the skin (well, into the non-exfoliating layers of skin).
We have archeological records of tattooing going well into pre-history (the tattooed iceman dates at 3300 BC). The word itself sources from "tattau", a Tahitian word which translates essentially as "to mark".' -Shannon Larratt
nowadays, there are technology to remove the tattoo such as a laser. thus, meaning the tattoo is a tattoo till is removed.
She found ink missing in her design so she must go back to get her tattoo retouched.