Click on your ticker and it will bring you back to the Tickerfactory.
Enter your pin and click Edit/Update Weight Data...this allows you to change your weight and enter today's date for your graph, click next and your details are update and they will automatically update your signature here as well.
If you can't remember your pin you will have to make a new ticker.
See video tutorial below which will show you step by the step the process from making a ticker to editing and updating your graph.