Tattoo Girl

Tattoo inks have been described as "remarkably nonreactive histologically". However, cases of allergic reactions to tattoo inks, particularly certain colors, have been medically documented. Occasionally, when a blood vessel is punctured during the tattooing procedure a bruise/hematoma may appear. This is sometimes due to nickel in an ink pigment, which is a common metal allergy.
Tattoo removal
While tattoos are considered permanent, it is sometimes possible to remove them with laser treatments, fully or partially. Typically, black and darker colored inks can be removed more completely. An ink trademarked as InfinitInk is designed to be removed in a single laser treatment. The expense and pain of removing tattoos will typically be greater than the expense and pain of applying them. Some jurisdictions will pay for the voluntary removal of gang tattoos. Pre-laser tattoo removal methods include dermabrasion, salabrasion (scrubbing the skin with salt), cryosurgery, and excision which is sometimes still used along with skin grafts for larger tattoos.