First make sure it has plenty of water. I would try giving it a hide box or at least something it can crawl under to make it feel safe. Then maybe try leaving a fuzzy mouse in with it over night. If that still doesn't work maybe try a brained pinkie. If it still hasn't eaten in a few days, then try assist feeding it. I have rarely had to force feed any snakes, assist feeding usually does the trick most of the time.