Absolutely ice (a bag of frozen peas works GREAT!) and I would also suggest a non-steroidal anti-inflammatory drug such as Advil. If you are an adult, take 400-600mg (2-3 tablets) before you go to bed. Also evaluate the inside of your mouth. Is there a cut and did you have any bleeding? If there is trauma on the inside of your lip then rinse with warm salt water (1 tbsp salt to 8oz. warm water) 3-4 times daily until better. And my last bit of advice is to consider being nicer to your sister in the future. She may opt for something other than a shoe next time! Take care!