it sounds like it was quite some work, if the surgeon actually saw your nerve then the parasthesia you are experiencing is well expected. If the swelling is not visible it only means that the soft tissue is healing. While that happens faster, the bone could take another 3-4 weeks. Basically you have some unresolved hematoma in the bone putting pressure on your nerve. Try moist heat in the area and monitor closely, if you start having some moderation in pain and tingling in your chin and gums, then you are progressing fine. If the pain does not subside and/ or gets worse, then a closer look into the area is warranted..
Post -op pain associated with a surgical procedure is probably best managed by medication in today's pracrice. However, your condition may take pain killer on a timely schesulue, for instance, every 6 hours, in stead of pain as needed. If OTC pain killer is not effective , you may need to see your surgeon for further pain management.