You can fix crystallized sugar by remelting the sugar crystals and trying again. You may want to add an interfering agent, and of course you want to be careful not to trigger the crystallization reaction. This is easy for crystallized liquids – simply reheat the crystallized syrup and try again. Other confections may or may not be easy to fix, depending on the recipe. You might just have to live with it! (But don’t worry, crystallization doesn’t ruin taste, it just messes up the texture.)