The way a samsung display is built, you can certainly replace just the glass. The s5 active (and regular s5, very similar displays) are super thin and easy to break but if you've gotten into something into a layer of the display other than the glass trying to remove it, its likely the polarizer not the digitizer.
Basing my assumption of your repair level abilities on your question, I'd advise you not attempt this repair without substantial further research.