biswashkoirala on "[Plugin: My Custom Functions] Site down and no access to wp-admin"

I had installed this plugin and everything was fine. I had used image slider for the site. But the image slider appeared in all pages.

I searched inteet and found the following code that I had to put in header.php but mistakenly I added it to bottom of codes in this plugin. Now site is down and I don't even have access to wp-admin.

<?php
if (is_front_page() || is_home()) {
echo do_shortcode("[metaslider id=123]"); //replace 123 with slider ID
}
?>
My site is http://www.royaljk.com and I used Meta Slider plugin for image slider.
https://wordpress.org/plugins/my-custom-functions/

I read other posts and renamed the plug in folder as my-customs-functions_modified . My site is back online now. But I had added several codes in the plugin. Can I get back those codes?
I have access to my hosting through FTP.