For going on 2 days now, I have had a strange sensation/numbness on the left side of my face by mainly lower lip & nose. What could be the cause?

Trigeminal nerve. You have a problem with the 5th cranial nerve, which is called the trigeminal nerve. You're describing symptoms consistent with that -the middle branch of it in fact. You should call your doctor today and try to be seen. If you develop any rash in that area, you need to go to the ER now and ask for an Infectious Diseases doctor (someone who would know about shingles). Lyme or other causes possible.