Getting a tattoo is not a good idea when the immune system is not at 100 percent. You'll need your power and white blood cells to heal your tattoo, which the body won't be able to do if it already battles viruses and bacteria. Not to mention the fact that bringing your illness into the tattoo studio and risking passing the germs onto others, especially your artist, is very inconsiderate. Call and reschedule if you have an appointment once again when you feel good.