Tattooing is something that is needs to be placed in a cultural context. If you are, say, a native New Zealander, it's seen as culturally acceptable to be covered from head to foot with tattoos. The same goes if you are a hard-core gang-banger convict housed in the Pelican Bay SHU. If you are a Wall Street banker or a Mayo Clinic neurosurgeon, such "body art" might raise eyebrows, especially if you had SS thunderbolts on your neck and "F*** Y**" tattooed across your forehead...
For better or for worse, "extreme" tattooing, which I'd define as: 1) facial/hand tattoos, especially with; 2) antisocial images or language, is frowned upon by our society. Indeed, some mental health professionals consider facial/hand tattoos to be a sign of Antisocial Personality Disorder...😱
I'm sure that some non-criminal decent folk see nothing wrong with adorning their bodies with "artistic ink" and feel that their doing so is a matter self-expression and should be accepted by society.
If you feel this way, all I can say is do so at your own risk with the realization that other folks may and likely will have a (negative) reaction to seeing your tattoos... It's hard enough to get into med school as it is without having to risk dealing with the negative impressions tattoos might evoke from your interviewers.