You should probably go back to your dentist/oral surgeon to discuss the numbness.
As for the difficulty in opening, definitely take your pain medications (or anti-inflammatories) that were prescribed and stretch the jaw out some. Switch between ice pack and warm towels to help loosen the muscle. Also, has the swelling gone down over the last few days? If the swelling is worsening, it could indicate an infection. Are you on antibiotics?