I used to have a big Asian skincare routine and I actually found when I simplified it I saw better results. Asian skin care are usually big on hydration and nourishing the skin.
Drinking water and staying hydrated has made the biggest improvement in my Forehead Wrinkles. I can tell immediately if I am dehydrated by the lines in my skin.
While you are right about severe dehydration causing severe symptoms, I wouldn’t so strictly say it has no effect on skin before it has a direct one on your brain.
When you stop drinking water and a body feels a lack of it, it concentrates urine so you’d pee in dark yellow-orange, smelly urine. Next step is to extract water from the body cells… skin included. This is done so you have enough volume of liquid in your veins. And loss of water from brain cells happens as an absolute last measure, when the body can’t do anything to stop it.
There is a test we do, called skin turgor – pinching slightly the skin atop of the back of your hand, or belly. If you’re dehydrated, a kind of lump forms and stays for a second or two. If your not, the skin goes back to the way it was instantly. And this happens way before a person develops any noticeable “brain” symptoms.
So, drink water, folks!