hello thanks for consulting at hcm..
Tongue and
lip numbness caused by lot of causes such as neuropathy, side effects of some medications, vitamin deficiencies,,it could also be due to mild
allergic reaction..
It also could be
burning mouth syndrome,, even multiple sclerosis,,
Since in your case it been there from a year ,, so it belongs to chronic causes of numbness,,
So kindly contact a oral physician for complete blood tests, and consult a oral physician and
neurologist for a check up and treatment,,
hope it helps,,take care,,