I sprained my ankle last night running. what's the healing time like for a sprained ankle? should i go see a doctor?

Varies: Mild sprains 1-3 weeks, moderate sprains 2-6 weeks, severe sprains can take several months to recover. It would be better to see a doctor just to be sure as well as to recommend appropriate treatment.

Ankle sprain: It depends on how severe your sprain was. In the meantime you should rest and elevate your ankle , apply ice and use an elastic bandage for compression.