No need! I've had a couple of frogspawns that have lost a head or two, but the main colony will survive (assuming the death of the single head wasn't due to declining parameters).
If you have any shrimp or hermits as part of your cuc, they will take care of the worst die off, if anything, just run some carbon/do a small water change to ensure things stay stable and give it time. If there is even just a little bit of living flesh left inside the skeleton it will eventually grow back over the exposed skeleton.
If you've ever seen sombody frag a frogspawn without a band-saw, they generally just snap off a branch, when they do, you can see the part they snap is all skeleton, there is no living tissue within that part of the coral, so even if one head dies, unless it is touching another head which may pass on some tissue necrosis, there is no way for that single head to pass on the death through the skeleton of an established head.
Hope it helps!