From what I understand, you have noticed these changes for the worse in your skin since you moved out of home and into hostel three years ago. This is not surprising, as this change must have affected your entire lifestyle, including your diet, your sleep cycle, and several habits directly relating to grooming and hygiene. However, you yourself are in the best position to determine exactly which changes have had this effect on your skin.
The darkening of your skin is most likely due to increased exposure to sunlight. Since you have moved into the hostel, you are probably spending a lot more time outdoors, which has given you a tan. If the tan bothers you, you should start using a sunscreen whenever you go outdoors during the day, and in addition cover yourself up as far as possible.
The loss of the glow that you say your skin once had may also cause it to look darker that it really is. This dull skin can have several causes. Ensure that you drink enough water daily, and that your diet is healthy and balanced. Eat lots of fruits and vegetables, and see that you get enough exercise daily. At the same time, your skin also somehow seems to be oily — is this only certain areas, or does your skin look dull and oily at the same time, or were you only referring to the darkening when you said the glow has gone? In any case, these measures along with some investigative work on your part should be enough to solve your problem.
answered by M W