Well, yes, generally speaking, strabismus can be caused because of the injury to the head. According to the researches, strabismus is typically caused by injury to the eye orbit. And at the same time, injuries to the brain, such as with a stroke or head injury can lead to strabismus too. So you should take care. And you should know that strabismus may be decided as either constant or intermittent, based on the frequency with which an eye deviates. For the causes, there are also some other factors, such as sickness or stress. Anyway, just be careful about it.
Some people getting strabismus are born to be. And others get this eye problem because of the after period development. Thus, it is possible to get strabismus because of head injury. Once the head gets hurt, the eyes nerves will be in disorder. That may cause the strabismus. You should go to the hospital to ask whether there is the curing way to heal it.
So, it seems that your head injury is quite serious, since normal shock would not lead to strabismus. Anyway, it is true that some hard head injury could give rise to strabismus because the visual nerves are damaged, so that there would be some trouble for you to see things. My advice for you here is to get some professional treatment, maybe some surgery, and see if your strabismus could be cured.