What is the penalty for doing tattoos without a license?

Yes, you can get into trouble without being licensed. The only unregulated states are New Mexico and North Dakota, you could scratch in those states. If someone were to get an infection from one of your tattoos, you would be responsible for their health care, and you could be subject to a fine and/or jail time. Most states it is a misdemeanor to be tattooing without a license. best to do it right and get yourself an apprenticeship, most states now require a formal apprenticeship to become licensed.