St.John's Wort Oil

Hello everyone! I wanted to see if anyone could help me out with some information. I'm a nurse who basically stands all day at work. I'm starting to get bad sciatic nerve pain. I had a suggestion from a friend that St.Johns wort essential oil helps with nerve pain/muscle aches. I know ingesting St. John's wort isn't advised while pregnant, but I can't seem to find any information about using it topically. HELP! I have an appointment with my OB/GYN on Monday but I just wanted to see if anyone new any info. I'm new to using essential oils and would love to hear some feed back!  Thanks =)