It is recommended to wait at least 24 hours after getting a tattoo before drinking alcohol. Alcohol thins the blood which can take the tattoo's pigment off parts of the skin.
It's recommended not to drink alcohol 24 hours before getting a tattoo, and many artists don't tattoo a person who has been drinking. The tattoo artist should provide aftercare instructions to follow. The tattoo should not be exposed to liquids for the first two to three weeks except when it's being washed. Antibiotic ointment is typically used on the tattoo for the first two weeks, followed by skin cream or lotion.