Hide custom meta data if empty

I have a custom field created for WooCommerce products.

I am using the below code to create

// ADD CUSTOM WOO DATA
add_action('woocommerce_product_options_general_product_data', 'woocommerce_product_custom_fields');

// Save Fields
add_action('woocommerce_process_product_meta', 'woocommerce_product_custom_fields_save');


function woocommerce_product_custom_fields()
{
    global $woocommerce, $post;
    echo 'div class="product_custom_field"';
    // Custom Product Text Field
    woocommerce_wp_text_input(array(
        'id' = '_sales_email',
        'placeholder' = '',
        'label' = __('Sales Email Link', 'woocommerce'),
        'desc_tip' = 'true'
    ));

    echo '/div';
}


function woocommerce_product_custom_fields_save($post_id)
{
    // Custom Product Text Field
    $woocommerce_custom_product_text_field = $_POST['_sales_email'];
    if (!empty($woocommerce_custom_product_text_field))
        update_post_meta($post_id, '_sales_email', esc_attr($woocommerce_custom_product_text_field));
}

The Code works well, and displays the data on the product page.

I am displaying the data via a shortcode.

div class="dbtn_sales"a href="mailto:[foobar name=_sales_email]"Email Sales/a/div

The problem I am having is hiding the data if the field is empty..

I have tried

if( get_field('_sales_email') )
{
    //echo the_field('_sales_email');
}
else
{
    echo "style.dbtn_sales{display:none !important;}/style";
}

but I'm getting nowhere... Can anyone point me in the right direction here?