Cell damage is when something bad happens to the cells in your body. Cells are like tiny building blocks that make up the different parts of your body, such as your skin, your muscles and your bones. When something bad happens to your cells, they can't work properly and this can make you feel sick. This can be caused by a lot of different things such as accidents, germs, or even unhealthy habits like eating too much sweets or not getting enough sleep. Cell damage can also be caused by things like radiation or chemicals. Just like a building, if something bad happens to the cells in your body, it can be difficult to fix them, so it’s really important to try to prevent damage to your cells so you can stay healthy.