Editing just one line in a (child) theme

My website https://www.vipjamaica.com uses a theme that provides social media links at the top and bottom of the page. It provides a spot for facebook, twitter, linkedin and youtube. I don’t use linkedin much so i changed that link from linkedin to instagram. To change the icon I had to edit the header.php file, but ofcourse everytime I update it goes back to linkedin.

I created a child theme to solve this problem and do other edits but now that means my header file will never be updated, and now, since the last update, my website has appeared to crash. I’m just going to remove the header file from the child theme for now though, sure that will sort that out.

Is there anyway to change just a single line out of the header (or any) file by using the child theme… or any other way to solve this problem? Please help.