Body changes in fat and muscle, as TG stated, may effect existing or future tattoos. Tattoos may change as you lose muscle and fat is redistributed under HRT. So, under HRT, just know your body will change, and tattooing may be a bit risky for some. Not all people change dramatically with HRT, some change very little, some change quite a bit. No standard there. If moving to MtF, just don't tat the muscle areas ... they will shrink! Your back is prolly fine, though. Good luck and post a pic of the back tattoo! ๐