Dog and Essential Oils?

I have chronic back pain and the remedy that seems to work best for me is putting a drop of peppermint essential oil on my back before bed. I have an australian shepherd who sleeps with me. The smell is pretty strong to me at first so i’m sure he can smell it as well. Could he potentially get sick from this small exposure to the oil? I throughly wash my hands after application so the only place it’s on is my back which he has no direct contact with.