Whether in a car door, with a hammer or a bad fall, smashed thumbs happen. As long as the injury isn't too serious, a smashed thumb or finger, and the pain associated with it, can generally be treated at home with some simple remedies. Next time you accidentally smash your thumb, you'll know how to handle it.
Evaluate the damage. Try slowly moving your thumb; if it's very difficult and it seems there may be broken bones, seek medical help. If blood pools under the nail, this can lead to more problems, so call your doctor for advice. Also if there is severe bleeding that doesn't stop after applying pressure for 15 to 20 minutes, seek medical help.
If you feel that the thumb can be treated at home, begin by cleaning the area. A broken fingernail or cut can get infected, so clean it with some warm water and antibacterial soap and apply an antibiotic ointment to help fight infection.
Bandage your thumb. You may also want to put a splint on the thumb to keep it from moving too much. A key to helping your damaged thumb heal and ward off pain is to not move it too much; the less you use it, the faster the tissues can heal.
Keep a cold compress on hand. To reduce swelling and fight pain, apply a cold compress a few times a day for 15 to 20 minutes. Or use a bag of frozen peas, a bowl of ice or ice wrapped in a washcloth. To further help with pain, take an over-the-counter pain medication to help reduce pain and swelling.