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If pain from a sprained finger is severe or lasts for more than a couple days, schedule an appointment with your general practitioner. They'll be able to assess the damage to your finger and determine whether or not the ligaments are sprained. Go to a local Urgent Care center or Emergency Room if you're unable to bend your finger after the incident or if the pain from the injury prevents you from going about your daily routine. Tell the doctor when and where the finger was injured. Also describe how you sustained the injury (e.g., if you caught the ball wrong in a game of baseball). Mention what angle your finger was at when it was injured and what direction the injury came from. Tell the doctor how severe the pain is, and whether it's become more or less painful with time. Also make an appointment if you have a mallet finger, since the condition needs to be treated by a medical professional. The doctor will most likely perform an X-ray or an MRI scan. Both of these scans allow the doctor to get a clear image of the bones and ligaments in your finger. An MRI in particular will allow the doctor a clear look at the ligaments inside your injured finger. After viewing the scan results, the doctor will be able to diagnose whether or not your finger is sprained. Neither the X-ray procedure or the MRI procedure should cause any pain or discomfort.
Visit a doctor if your finger is still swollen, bruised, or painful after 48 hours. Describe your finger injury to the doctor. Request an imaging scan if your doctor can't visually confirm a sprain.