First question, is Occupational Therapy part of your recovery protocol? Did they suture muscle, tendon, or both back together? Are you currently splinted?
Regarding the sensation. Peripheral nerves (the one's outside the spinal cord) can regenerate. The problem is, they only move about 1mm a day. Dependening on if the nerve was traumatized vs. lacerated; and your age; will also dictate healing ability. I'd say your chances of sensation returning are better than not.
It also sounds like it was the precutaneous branch of the median nerve that was injured, not the radial? If this is the case, you are much better off given the radial nerve supplies most of the motor innervation to the thumb. A functional thumb is part of what classifies us as human.
Best of luck with your recovery.
Manolito