OP can elicit dormant herpes infections. The old posts I read when I had a terrible sore on my tongue suggested it was from oregano oil, but I believe just the OP process is enough to do it. The good thing that I read was that if oregano oil makes you have an outbreak, it can be the last one you will ever have.
You might want to add some oregano oil to your base oil. Although I really would not add it to coconut. I am reading so many posts with people pulling with coconut and having uncomfortable reactions. There is no point in equating discomfort with efficacy, and other oils are equally beneficial in their own ways! So if you are using coconut, having a bad reaction -- switch oils, or mix another oil with coconut, or cut down -- the bad reaction means it's time to give it a break!