Wexan: The facial (7th cranial) nerve controls facial MUSCLES, but facial SENSATION is controlled by the trigeminal (5th cranial) nerve.
So if you are having “invisible insects” on your face, or numbness, tingling, pain, odd temperature sensations, etc., that would be the trigeminal nerve. This is also the nerve that causes headache pain, I think.
Your question of whether I “formed any ideas” about what caused/causes my neurological oddities opens a can of worms. 
The sad truth is (as you’ve probably found out) that neurologists often cannot explain a person’s weird symptoms, or they aren’t interested in trying to.
One neuro initially all but told me I had MS, but later he took it back, and all subsequent doctors have essentially said I don’t. On the other hand, they never had any PLAUSIBLE explanations for my symptoms.
I finally, recently, concluded that I must have some teeny-tiny “benign” form of MS, though I would NEVER say that to a doctor. (Just like I had to diagnose myself with MAV, because no doctor EVER gave me ANY explanation for my dizziness that held up to scrutiny and testing.)
I concluded this because subjectively I fit the essential, basic, boiled-down definition of MS: damage to at least two different parts of the central nervous system separated in time, with no better explanation.
I have (minor) brainstem abnormality and spinal cord abnormality, though both are apparently only SENSORY in nature, to which the docs ascribe no importance. (If my major walking trouble–I can only go one or two blocks now–is due to the spinal cord, then it’s not merely sensory damage, but I truly don’t know why I can’t walk sustainedly anymore–it may be joints or muscles.)
The brainstem abnormality is proved by auditory brainstem response (ABR) testing as well as strange sensory symptoms. The spinal cord damage is proved by my long-standing Lhermitte’s–electric buzzing in my leg(s) when I bend my head down.
I have two red-flag symptoms for MS: Lhermitte’s and bilateral trigeminal neuralgia (one painful episode in 1999 but mostly painless shocks since then).
But since my reflexes, eyes, gait, and MRI show no signs of MS over many years, the doctors have no objective, specific findings for it and so they just call me a hypochondriac. (My MRIs had an increasing number of little white lesions, but they are not specifically MS-looking–could be from migraine and/or “small vessel disease.”)
So–objectively I don’t have MS; subjectively (that is, in my thinking), I do–but not “real” MS, just a little shadow version of it, perhaps. That is just my theory. Because there IS no other plausible theory. Other things have all been ruled out. But I do NOT meet the doctors’ definition for MS by a long shot (because they need objective physical evidence–though they ignore my ABR and MRI results).
They have tried to do a spinal tap to help rule it in or out, but they have been unable to withdraw spinal fluid. And there are other tests that they never did. But I accept that officially, practically, I don’t have MS.
I just use it as an explanation to settle my own mind, because otherwise I would keep being driven nuts by that buzzing every time I bend my head down, thinking “What IS it???”
I know you’ve had a long, hard time figuring out what’s wrong with you, too. What do you think about your own case?
Nancy