There is a layer of co2 protecting you beer, so more than likely everything is fine. That same co2 that evidently knocked off the airlock, is also keeping most airborn matter from getting in.
Since your beer is in secondary it should be all alcohol at this point, so nothig really should harm it anyway.
I give your beer a 99.5% survival rate.
Take a look at the stories in this thread and you will see how hardy your beer actually is.