I didn't wear mine (a small stud in my nostril) for the first few months of school, then after seeing residents and attendings with piercings and small tattoos, I put it back in. No one has said a word. And I have a visible foot tattoo that technically isn't allowed in the hospital, but no one says a word when I wear a dress with flats and its totally visible. Present yourself professionally (clothing, demeanor, confidence) and you'll never give anyone pause.