If you don’t have a commercial version around or you need cooling in a hurry, you might benefit from making your own ice pack to help address an injury. It’s easy enough to do, and if it’s something you need to reduce pain, you can put one together quickly.
The simplest version takes a resealable bag and some water. While most might simply put ice cubes in the bag and attach that to the lower back, there are alternatives that might last longer.
For example, you can combine water with isopropyl alcohol. This will create a more gelatinous mixture instead of solid ice cubes, which could distribute the cold more evenly.
As helpful as this is, it’s only a home remedy. For real assistance, you may need to visit a licensed chiropractor.