custom header on mobile

I’m using Highend with header layout 2 and a tagline. Works great on desktop, but I need to keep it on mobile.
On mobile, header displays only the logo, but I need an additional element, even just a text link, to display a 24h help link. I’ve tried a show-mobile and hide-mobile class, and it works fine on content pages, but on the header tagline. What can I do?

http://www.melcher-prescott.com/review