On the Beit El Yeshiva Center site (originally posted by jake, and used by yydl in his answer), someone asks about:
a new tattoo ink called freedom-2 that is permanent, but when you want to remove it, there is a formula that breaks it down and the body absorbs it."
Rabbi Yitzchak Grinblat says:
Halachikly even this tattoo is Asur because of Marit Ayin.
Another person asks:
Is it permissible to have permanent make-up done?
Permanent make-up is applied with a needle under the first skin layer and usually stays for about a year. Does this fall under the prohibition of getting a tattoo or is there a Heter for this?
Rabbi Chaim Tabasky replies:
Several important Poskim have forbidden the use of permanent make up because of the similarity to tattooing. Because there are different methods, one should consult a halachic authority in the specific case.