Infections- if the needle used in tattooing is dirty or not sterilized properly it can transmit many serious infections from one person to another. like Hepatitis B,C, HIV and any infection like Infective Endocarditis.
Allergies- every person is allergic to something so it might be ink or dye used in tattooing. Allergies can be very trivial like redness,itching to very serious like Anaphylactic reaction which is a dangerous condition present as shock, difficult to breath due to laryngeal swelling and Broncho-constriction. person may die some time if not taken care on time.
Scarring- ink in the dermis incite inflammation which ultimately results into production of collagen tissue which creates the scarring of skin. some people are more prone to this thing and may develop Keloid a big mass of scarred tissue.
Granulomas- these are small nodular tissue swelling in the skin produced due to body tries to defend against the ink which is treated as foreign stuff by immune cells. cells eat up the ink and surround it all around by scarred tissue.
MRI issues- MRI may burn or distort the tattoo. so people may have burning and swelling.
