Oops, to answer your question about permanent damage, it depends on how
much crap got on your diaphragm, along with the ice. The spring should be
fine and these diaphragms are very durable. I've never looked at these, but
I'm guessing you can take these apart (not sealed as some are,) clean and
re-assemble. Also, make sure the vent has a screen and that it is pointed
away from likely debris path.
Miguel