Thanks for sharing your concern.
As your history suggests that you required root canal treatment
long back but you could not get it done,so it is quite possible that an abscess
has developed in the concerned tooth and it has affected the surrounding area too.
An infection might have spread and has been putting pressure on nerves of the face causing temporary numbness
Now do not worry and do not delay it anymore.
visit your dentist
ant get x ray done so that the under lying pathology can be traced and treated.
For any developed abscess,it has to be well drained,where as any cyst or tumor has to be managed differently.
and antibiotic can be started after oral evaluation by dentist.
Hope it helps.