Houzz icon

On March 31, 2016 I submitted a request about adding the Houzz social icon to my header. The instructions you sent worked great: I did insert it and it worked fine for several weeks. Now, the Houzz icon is no longer visible. I assume it may have disappeared when I updated the theme, but I’m not sure. Would updating the theme have removed it? Do I need to be making the code change in a child theme rather than the original Enfold theme? If so, how do I create the child theme so the logo and other change don’t disappear when I update the theme? Thank you.