It may be the roots were destroyed, in which case, it won't grow back. You can check by digging around a bit to see if the roots are still there and are viable. If not, then selecting odd plants here and there from the other patches and transplanting them into the bare area should work, but will take some time to spread out and fill the area. If you want to do that, wait till spring is just beginning, and ensure you water well and keep watered as necessary.
Otherwise, for quicker results, it means replanting with newly purchased plants.