Frozen food with ice crystals on the frozen food or food that has freezer burn is very safe to eat although the taste can be different and the texture of the frozen food can be different as well.
But the food even with the ice crystals or freezer burn is still safe to eat.
Ice crystals can form on frozen food when the water molecules escape from the frozen food and then that allows some oxygen molecules to get into the food and those oxygen molecules can then dull the color and modify the flavor of your frozen food.
But there's nothing else wrong with the food when that happens and there's no need to throw it out because it's still safe to eat.
Nothing bad will happen to you if you eat freezer burned food or food with ice crystals as I've done it several times for many years and never have I gotten sick from it.