None of these work!! seriously! Tune just sounds all warped when you get it flat again anyway! lol. Plus re-heating it and flattening it that way wont work either, just melts the grooves flat aswell. If some of them havent melted flat already, when it warped the first time.
And the last suggestion will just snap your vinyl!!!
Unfortuantely mate that tune has gone to Vinyl Heaven and will never return!
Its a proper bummer mate! Best thing to do is at the first opportunity you have move your decks etc into a room with no windows.
Only thing you can do is just make sure it never happens again! lol..