The ink used in a tattoo is placed through a needle into the dermis, or second layer of skin, according to Dartmouth Medical School. The epidermis, or top layer of skin traps the ink to create a permanent design.
A tattoo needle will only penetrate an average of one millimeter into the skin. Still, the epidermis will need time to repair itself after a tattoo is applied, usually two to three weeks on average. According to the Harvard Health Blog, a new tattoo should be treated as an open wound. Aftercare includes avoidance of the sun to protect against blistering. The affected area should also be kept covered and dry with a clean bandage till the skin is fully healed.