question on essential oils+ essential oils for auto-immune disorders (hashimoto) and daily fatigue

Hi,

I'm passionate about EO and have bought many books and am now studying them.
what I'm looking for are testimonials from people. what does help for their issues, if it's best to take them internally or externally. is it best to rub them on vitaflex or rather on the organ itself etc..

I have read that myrt is the one to take for hypothyroid, rub on the throat where the thyroid is.

I take lemon internally for cravings, fatigue, viruses, good digestion. (have just started it), usually it's coupled with peppermint but the latter is to be avoided when used for a long period.

I rub black spruce on my adrenals every morning.

I also use EO in my cosmetics.

what do you think? is there a limit in their uses?

I suspect even when used in cosmetics they enter the blood too...