Right lower teeth numb and swollen but no pain why?

Pressure: Numbness can be caused by internal pressure on specific nerves in the area. Causes can include an infection or a cyst. Call a local oral surgeon asap to be evaluated. Once the cause of your numbness is determined, you can be treated. Pain is not always present. Do not wait.

Oral surgeon ASAP: Sounds suspicious for tumor. See oral surgeon or ENT ASAP.

Acute abscess: may be painless but still have a swelling present on the gum and often lip numbness.