Suggest Medication For Swelling Of Thumb Due To An Accident

My daughter (nearly 4) got her finger and thumb shut in a car door nearly three weeks ago. We got it X-rayed straight away, and they said nothing was broken. But the swelling in the thumb is taking a long time to go down (the finger looks fine, and is just a little tender) , and she can't move her thumb joint at all. Could it be broken even though the X-ray said not?