hello and a good afternoon,
welcome to the forum.
stress and lack of sleep are the two major causes of
dark circles under the eyes.
and you are undergoing both the conditions,.
proper sleep of at-least 6 hours is necessary not only to decrease your dark circles but also to decrease your stress and have a good quality of reading and studying time , as brain also requires some time to rest and the formation of memory occurs during sleep.
so i will advice you quality studying rather than overexerting yourself.
try using slices of cucumber on your eyes for atleast an hour a day, this will give rest to your eyes as well as keep the skin moist and nourished.
try using home made fresh cream layer on milk for your skin, this will give your the best result as there is no added artificial chemicals and so least chance of allergic reactions.
hope my advises will help you.
take care of your self along with your studies.