Here is a simple #DIY recipe for sprains and muscle pain and you don't have an ice pack. 2 parts water, 1 part rubbing alcohol (I like to use the green) and pour into a 1 quart size ziploc bag and put in the freezer. I like to double bag it. It should come out the consistency of a slushy and gives off more cold than a bag of peas. If it comes out hard like ice, just add more rubbing alcohol until you get your desired consistency.