It may grow back, depends how much of the eye was lost. Eyes are fairly complicated organs, and the whole eye stalk is very important and fairly complex for shrimp as hormones are produced there.
I looked it up a while ago, and most people report that an eye can grow back but that it takes a while, a good few people also say that their shrimps eye never grew back, but it could just be that they never waited long enough, or the shrimp died before it had time.
Some people have also said that the shrimp just grew mini-antenna instead of the eye, again, maybe there just wasnt enough time.
So don't count 100% on it growing back, but it is possible, and the shrimp will be fine.