Which cranial nerves could be affected/cause unilateral eyelid & brow dropping. It started as fluctuating but now there constant drooping?

Get a Neurologic Exa. Eyelid drooping is a sign of neurological derangement of some type. I would advice that you see a physician ASAP, preferably a neurologist although a Primary care doctor to start with may also be a reasonable option to consider. But do not delay it more than 24 hours as you may need urgent intervention with medication. Good luck.