Never put them in the refrigerator because they will be fragile when you take them out and melt quickly. Unless you want to keep it inside the fridge for the rest of your life.

You can put some starch on the surface of the lollipop and put it in a cool place, preferably wrapped in a paper towel, don't receive sunlight, and don't put it in a room where the temperature changes a lot. Don't move it if you're fine, it's the best way to preserve it-~

Another one is to eat it, haha-