If its continuing to swell, there may be an infection. You should get it evaluated by your dentist to rule that possibility out. Also, how long did it take to swell up? Did it take a few hours or a few days?
The numbness will need to be re-evaluated too. Was it a wisdom tooth you got removed? There's a risk of nerve injury from the extraction or from the injection itself? It needs to be monitored and observed. The nerve injury could become permanent but it will take up to 6 months to heal. If at 6 months it doesn't heal, it is most likely permanent.