Use gua sha

Hey!!! I received this gua sha in my goodie box, but I have a few questions about this. Does this large size also work for the face? It was recommended to use this with an oil. I have mixed - oily skin. Which oil should I use for this (or other product)? What oils do you use for the body? Have you noticed an effect on the face and/or body? Thank you!!! Xx

Translated from Dutch by AWS