I can imagine many interviewers being ok with small earrings (studs) and/or a well-trimmed, neat goatee. I can't imagine what sorts of clothes a man could wear to an interview that wouldn't cover most tattoos -- since long sleeved shirt and jacket, pants, shoes, and socks usually hide most of our bodies, we're looking at a tattooed hand, neck, or head/face. Which I can imagine might spook an interviewer or patient (or two)... I think interviewers are pretty good about taking the person as a whole, and listening to what you say. Your appearance will tinge this impression, to be sure.
I think you knew the answer to this question before you posted. Why did you ask?