I have not for skin cancer but did for another skin-related ailment or just after 1st lockdown. The dermatologist asked me to send a picture of the skin and then we had a video interview. She said that "maybe" I had such and such thing and gave me medication in case I had it. It turns out I didn't have it. Whereas in office they seem to be much more precise. I would think online would be fine for exchanging information, discussing biopsy results etc, but not for skin examination. At present dermascopy is used in at least some dermatology offices, to have a notion as to if a new bump or spot is cancerous. That is not yet possible online, to my knowledge. Yet if it is impossible to get to an equipped dermatologist the online option must be better than nothing, possibly linked to one of the new skin cancer related apps which record evolution of skin bumps and spots.