Need expert advice. What signs indicate dental paresthesia is going to heal, and what indicates that it isn't?

Time. Partial numbness has a greater change of complete resolution than total numbness. Early improvement is a favorable sign. Total numbness for a long period of time is unfavorable.
Paresthesia. is a rarer complication of lower teeth dental treatment (e.g. implant, root canal, etc.). The sensory deficits or numbness is the major symptom. See your dentist for post-op evaluation and a proper parasthesia treatment as early as possible. The sooner rather than later for a better outcome. Good luck.