do you think you could use minor illusion to create a mirror image of yourself to help with shaving and such. Or maybe just your head? Asking for a wizard friend RAW, it needs to be within a 5-ft cube, and is an illusion by nature, so it cannot interact with anything physical. However, your DM can decide otherwise!
— Matthew Mercer (@matthewmercer) June 12, 2018
For anyone to be able to see the Illusion at all, it has to reflect and absorb photons. Therefore, if you make a thing that’s silvered, it would reflect back like a mirror.
It could generate photons or it could affect the mind directly