Fainting, secondary to harsh and/or prolonged cough, is common and can be very dangerous. Your injuries were bad enough but such falls can result in even worse injuries, such as a fractured hip. Cough, if fairly constant, can also result in dehydration and that can cause a quick fall in blood pressure when moving from lying in bed to standing up, especially if the change is made quickly.
You need help and you need it now. Help from both friends or family members and help from physicians, able and willing to treat more than your lacerations. If you have not already done so, you should seek this help on your own. You may even require hospitalization, if still at home. Whatever happens, you should not attempt to deal with this serious illness on your own. That could be fatal.
Good luck