Very interesting article. You’re right, the derm says some very convincing things and there are some studies showing sericin (silk protein) may have anti-aging properties under certain conditions. Example: published in the International Journal of Cosmetic Science
I’m still skeptical, however, because rubbing a cocoon on your face is not a very efficient way of delivering sericin to the skin and the amount of the protein that can be delivered that way seems like it would be very low.
Those are my assumptions but when I have time I’ll dig around a little bit to see if I can find something more definitive.