Yes, we are experiencing widespread damage to many landscape plants due to the freezing temperatures we just had, especially to broadleaf evergreens and marginally hardy plants. Many, such your hollies, will most likely be fine. They may drop the damaged leaves eventually but should put out new growth this spring. Right now we are asking everyone to be patient and wait until spring to see what kind of damage we are actually dealing with. At that time pruning can be done to cut out dead tissue if necessary or even removal of dead plants.