They haven't find a cosmetic way yet to make someone look younger (besides make-up), let alone a medicine or something like that. Most people are happy getting older though. It's only people like us, who place value on looks, that have difficulties getting older. Also, lots of people that are dissatisfied with their looks have mental problems (weather it's because of their looks or they already had it) and missed out on alot of things in life. It's easier to become older if you had a satisfying live and if you were satisfied with yourself. If not, it becomes difficult to accept. If you can't accept your looks, how can you accept getting older?
