Hi! About a month ago, we got an X-ray and found out I sprained my ankle. Right now, there's no pain but it is still swollen. Why is that? Thanks!

Depends on. severity of injury. If it is still swollen after one month, it sounds like a severe sprain. If there is no instability, the swelling should subside. If it persists, or if you develop worsening pain or any instability, return to your doctor for more tests.