It is natural for raw honey to crystallize as the glucose in honey precipitates out of liquid honey. It is absolutely fine to consume crystallized honey.
Simply place the jar of honey in lukewarm water after removing from heat and let the jar of honey sit there for some time till the crystals dissolve and you can mix it all up with a spoon. Be careful not to boil or scorch the honey.
You can also eat honey in a crystallized form, spread it on your warm toast or add a spoonful in your hot tea!