Keep the product. It is evidence that the item was indeed defective. Be sure to save the sales receipt, instructions, packaging, manual, and accessories.
Never return the product to the manufacturer. It can easily get lost or misplaced.
When it is not possible to keep the product, gather as much information as you can about it. Take pictures of the product. Look for:
Seek medical help. A doctor can help you identify, diagnose, and treat injuries invisible to the naked eye.
Document evidence. Photograph or videotape the product and injuries.