There are a number of reasons that lips can become numb, and causes can range from benign and temporary conditions to chronic and serious illness. Causes of numb lips can include:
Dental visit with an anesthetic such as procaine (Novocain)
Prolonged cold exposure
Pollen food allergy syndrome (PFAS)
Also called oral allergy syndrome or OAS
Is an allergic reaction to a plant-based food, such as raw veggies, fresh fruits, or seeds such as fennel or sunflower
What Symptoms May Accompany Numb Lips?
Other symptoms that may accompany numb lips include:
Dental visit with an anesthetic
Chills
Headache
Shivering and chills
Swelling and/or itching of the tongue, throat, or roof of the mouth