"When you spend enough time in water, the skin on your feet and hands gets wrinkled, or "pruned". No, it doesn't age you: If it did, there would be a lot of filthy people around, clinging to their youth. After you get out of water, your skin eventually returns to normal. The reason for this has to do with how our skin is composed.
Skin is made up of three layers. The deepest layer is subcutaneous tissue that includes fat, nerves, and connective tissue. The second layer is dermis, where you can find your sweat glands, hair roots, nerves, and blood vessels. The top layer (the wrinkle-maker) is the epidermis. The surface--or top outer layer--of the epidermis is made of dead keratin cells. Keratin, which is also part of fingernails, is there to protect the rest of the skin. Your hands and feet have the thickest layer of keratin; since you use these appendages all the time, they need an extra protective coating. We couldn't do much if the skin on our hands and feet was as thin as that on our eyelids.
So what happens when you go for a swim or a soak in the tub? The keratin absorbs a lot of water. In order to make room for it all, wrinkles form and the skin plumps. Why wrinkling as opposed to just plain ol' swelling? Because the top layer is connected to the other layers of skin, but in an uneven manner. The bottom layers of skin are more waterproof than the top layer, so the water has to sit there for awhile before it can be absorbed. Water that is not absorbed by the skin will evaporate, which returns your skin to normal."
To read more on this: You will need a copy of the book,
"Why Do Men Leave The Seat Up?"