Three doctors say it is definitely a coincidence but don't want to say it is the cause.   Perhaps they are afraid that the facial exercizer company will defend itself by attacking the dermatologist's reputation.   I used a facial exercizer for a few months but found it uncomfortable and stopped.   A year or two later I got little dry spots on my face.   The ones over my lip turned pink.   There were NONE on my nose where you would expect to have sun damage but there were also no facial exercizer contact points on my nose...yet there WERE several underneath the nose which would have had less sun exposure.  Doctor did not treat it correctly until cutaneous horns grew out of one and I told them I could feel a root growing underneath the skin to another location.   A few weeks of efudex and I am hoping all is okay now but not sure yet - My skin looks pretty good now but I am in follow-up in case something starts back again.  I held the exercize mask up to my face and the damage spots matched up.  I switched doctors, too.   Think twice before using these exercize machines that run off of batteries or electricity.   I do not have "proof" but I know for myself that it hurt my skin.