Essential oils have tons and tons of applications and uses from simple things like upset stomach or headache to serious diseases and ailments like diabetes and cancer.
The oils can be ingested some of them and most of them are rubbed directly into the skin. You need to talk to them beforehand so that you are getting the right oils and use them the right way.
You want to make sure you are getting high grade organic oils. Nothing with additives or named anything but a plant name.
Our family uses this site and the owner Lena Hunt is amazing nutritionist and holistic medicine essential oils expert. She blends all the oils herself for her clients to order and they work amazingly.
I would email them and tell her your specific problem and they usually email back very quickly with advice and how to use essential oils for your specific problem.