When you uninstall the SuperLemon WhatsApp app from your Shopify store, the app automatically removes all code from your storefront. We do not leave behind any code in your theme.liquid file, like many other apps do.

However, if you had manually added the script code to your theme.liquid file, you will need to navigate back to the file and remove the script code for the button to stop showing on your store. You can find the guide here.