Your mechanism of injury
certainly sounds dangerous and could have resulted in either a broken or a severely sprained ankle. Either injury can result in swelling and bruising. In some injuries, pain does not start immediately afterwards, but may come on gradually over the course of the next few minutes (which is what happened in your case) or even hours. Ankle injuries
as the result of athletic activities or falls are a very common complaint seen in the emergency department and outpatient care setting. To help determine if you should have x-rays taken to rule out a broken bone, your doctor
can use a certain set of criteria from his/her physical exam to help assess your risk. If you are tender to touch in certain parts of the ankle or are having difficulty bearing weight on your ankle, then your doctor will refer you to imaging.
Given the degree of swelling and bruising you are experiencing, you should contact your primary care provider or go to the emergency room for further evaluation.