Accidentally deleted a token or messed up your Fog of War? Good news. You can undo and redo practically every action you take on the battle map.
You'll notice these two icons at the top-center of your screen. The first one acts as an Undo for the last action, and the second one acts as a Redo. Keep in mind that both of these have keyboard shortcuts attached to them!
Please note that your Undo/Redo history will be cleared once you refresh or close the tab.