You have not mentioned exactly how you injured your finger, and exactly what damage the trauma has caused. "Smashed" can mean a lot of things, from lightly jamming your finger in a door to slamming it with a hammer. Is there bruising or bleeding? Is the finger swollen, and if so how bad is the swelling? Are you able to move your finger, and if not, to what extent is movement restricted? Also, how painful is the finger - is it constantly throbbing, or does it hurt only when you use it? The answers to all these questions need to be considered when decided how to treat the finger and whether medical attention is necessary. If you have suffered a serious injury, with severe swelling and pain, and severely restricted movement, you should visit a doctor as soon as possible. You may have suffered a fracture, and even a hairline fracture must be attended to immediately if the finger is to heal properly and return to normal.
If the injury is a minor one and you are really sure that there is no need for a doctor to examine your finger, then the RICE treatment is all that you need - rest, ice, compression, and elevation. First of all, you should avoid using your finger at all, at least for a couple of days, and possibly for a week or more. This allows the damaged tissues a chance to repair themselves. If you find that you frequently end up using your finger, then bandage it so as not to allow movement. Next, apply ice - this is in fact the first thing you should do for such an injury, as it greatly reduces the extent of inflammation and swelling. The best way to apply a cold compress is to wrap a couple of cubes of ice in a hand towel or some similar cloth, and then press this to your finger. Ensure that the cloth is clean at all times, especially if there has been bruising. Finally, if and when possible, keep the affected hand elevated to prevent fluids from collecting in your finger and causing more swelling. This is not as important for the hand as it is for the lower limbs, such as in the case of a foot injury, but it will still help. If you have bruising, you should wash the wound at least twice a day, after which you should apply an antiseptic ointment.
answered by G R