Medrol (methylprednisolone) dosepak; can it be used if your ankle swells?

Depends on the: Reason for the swelling. You don't really want to be taking oral steroids unless there's a condition which warrants it. Ankle swelling is a symptom, not a disease.

Not long term: While a Medrol (methylprednisolone) dose pack can reduce inflammation in the short term, it would be important to determine the underlying cause of the ankle swelling for long term relief.