Thanks for posting your query in hcm forum.
Numbness inside upper lip usually occurs due to-
Abscess formation due to periodontal infection/traumatic injury/deep caries.
A thorough clinical evaluation by a dentist
will help to interpret final diagnosis.
Pus has to be drained and curetted.
Analgesics along with metronidazole
has to be administered to relieve the underlying infection.
Meanwhile,maintain oral hygiene
Brush and floss your teeth involving all aspects .
mouthrinses to gargle.