Youth is lost on the young. Every day they're squandering their good looks, never appreciating that they don't have to worry about thinning hair, saggy eyes, or loose skin. But just wait till they get older. The day will come when they'll look back and pine for the past. Or maybe even take matters into their own hands...by going under the knife! Because that's what these 21 celebrities did as they aged over the years (over even months!) 1.) Sylvester "Rocky" Stallone is still the Italian Stallion. Imgur 2.) Vegas living has done nothing good for Wayne Newton. Imgur 3.)...