You have an "injury" to your inferior alveolar nerve since it is your lip that is affected. I would contact the doctor now to report the symptoms....and, personally, would not wait. Are you completely numb or just some...like when novacaine is wearing off after a dental injection?
The nerve could have been bruised and will recover only with time which is the most likely cause.
This is a rare occurence but there are times when nerves have been severed or "crushed" during tooth extractions and that being the case, you don't want to wait too long before you start looking into surgically repairing the nerve. Like I said, this is likely not the cause but if I were you, I would let the doctor know.
Post-op numbness is common, especially for deeply impacted wisdom teeth. Most cases resolve slowly within 6-12 months completely. If your symptoms are not improving in 6 weeks, you should go back to your oral surgeon.