There's a special blessing for the St. Benedict medal.
See http://www.osb.org/gen/medal.html
Print out the blessing and give it to the priest who will bless your
medal.
He doesn't have to be a Benedictine Priest but should follow the
approved formula.
Some links to articles about the Saint Benedict Medal:
https://christbearers.wordpress.com/2012/07/11/sending-the-devil-to-hell-with-st-benedict-at-your-back
http://www.wikiwand.com/en/Benedict_of_Nursia
https://en.wiki2.org/wiki/Benedict_of_Nursia
http://www.communityofhopeinc.org/Prayer%20Pages/Saints/benedict.html
http://www.catholicsacramentals.org/saintbenedictmedal
http://listverse.com/2013/05/21/10-amazing-feats-performed-by-saints
http://catholicism.org/ad-rem-no-190.html
http://www.wjpbr.com/benedict.html
On the Sign of the Cross:
http://www.catholicherald.co.uk/commentandblogs/2014/05/29/the-importance-of-the-sign-of-the-cross-must-not-be-lost
http://preparationforapocalypse.weebly.com/remedies.html
Ask a Priest:
http://www.catholicvu.com/3009.htm
Videos on the Saint Benedict Medal:
http://www.mashpedia.com/Saint_Benedict_Medal
True Stories:
http://newcovenantjournal.blogspot.com/2010/08/saint-benedict-medal.html
http://lasalettejourney.blogspot.com/2012/06/evil-spirits-were-particularly-enraged.html
Photos of St. Benedict Medal Tattoos:
https://www.google.com/search?q=%22saint+benedict+medal%22+tattoo&tbm=isch&source=lnt&tbs=itp:photo&sa=X&ved=0CBUQpwVqFQoTCNTr9P3fmcgCFco4iAodePML6A&dpr=1.2&biw=1138&bih=458
https://blog.adw.org/2012/07/the-many-disguises-of-satan
