A swollen finger can be due to a variety of reasons, and before you consider treatment, you have to determine the exact cause. A common cause of a swollen finger is if a bone is broken or fractured. In this case, you have to see a doctor so that the bone can be set properly and medication can be prescribed.
If you think that your finger is not broken, then there are some home treatment options that will alleviate the pain and swelling. If, for example, you determine that a cut or wound is responsible for the swelling, then the first thing that you have to do is make sure the finger is clean. Wash it with soap and warm water. Alternatively, use some hydrogen peroxide to sterilize the area. Make sure that you pat the area dry, and then apply some antibacterial medication. To protect the finger, use a bandage or gauze to cover the wound. Clean and change the dressing periodically to make sure that the wound is healing properly.
If there are no visible cuts or wounds and your finger is swollen, then you might have jammed or twisted your finger. In this case, you have to follow a regimen that athletes swear by: RICE. Rest, Ice, Compression, and Elevation. When apply ice, wrap it in a towel or use and ice pack. Apply it for 10 minutes and then give your finger a rest. You should then wrap a bandage tightly over the finger - tight enough to give it support but not too tight that blood will not circulate properly. After a couple of days, the swelling should go down.