You won't get lynched, but it will make a bad impression in Japan for the rest of your life and you'll constantly have to deal with the issue by hiding it, covering it up, keeping it concealed, or being prevented from applying for certain jobs.
Japan and opportunities, or having a picture on your arm. Your choice. There is NO positive to having tattoos in Japan. At least get it in a place that no one will ever see unless you show them (even then you just got yourself kicked out of most onsens I've been to). Getting them on your wrists, when you are planning to go to Japan, in my opinion is just social suicide and foolish.