What Causes Constant One-sided Tingling On Face?
If isolated ALS unlikely
Detailed Answer:
I read your question carefully and I understand the anguish you seem to be in.
First let me start by addressing what you seem to be your biggest fear ALS. Facial weakness is not a first characteristic manifestation of ALS. Generally it starts in the one of the limbs. Even in those forms starting in the brainstem it usually involves the bulbar region with symptoms like difficulty in swallowing or articulating words, drooling, facial muscle involvement is usually or a late phenomenon. The tingling also not typical, ALS is a motor neuron disease, it doesn't include sensory pathways which would produce sensory signs like tingling. So while I can't completely exclude ALS it is unlikely.
Now first of all you must make sure that there is indeed a facial atrophy. At times people have some degree of born facial asymmetry, try to compare a present shot with past photos to see for differences which might already have been there but not noticed.
If there is an asymmetry it may be related to the facial muscles or bony structures. Facial muscles should be accompanied by abnormal findings on those strength tests you mentioned so it kind of makes facial atrophy unlikely so dental causes like malocclusion or problems with the temporomanibular joint might be occluded.
If possible I would suggest you uploaded a photo. I understand you might not want to show your face, perhaps you could hide your eyes (not ideal for me but would render you unrecognizable and better than nothing).
If I were to assume there was indeed a facial atrophy, then I believe it would be needed nerve conduction studies/electromyography confirm nerve impairment and degree and a head MRI to check for brainstem involving conditions like a benign tumor such as meningeoma, a vascular malformation or infections like Lyme disease. But first and foremost they should be preceded by a neurological physical exam by a physician to check for involvement of other cranial nerves.
I remain at your disposal for further questions.