As long as the branches bend without breaking then they might make it back.  If they are brittle cut it back until you reach supple living branches.  Feed the roots with Holly-Tone, a granular long term feeding.  More importantly, get some Mir-Acid soluble food.  Dilute as directed and sprinkle it from a watering can all over he branches leaves and stems.  This type of food can be absorbed directly into the cells of the bark.  It will quickly stimulate bud and leaf growth.  It is an emergency method of getting nutrients into the plant quickly.  Do this every week and a half until mid June when it starts to get hot..  By then you should see a little new growth.

You can use Repels-All animal repellent spray to keep the deer from doing further damage.  Apply it in fall and winter one a month on days that are above freezing.