Man, I hate when that happens! Yes, we've all done it - or will soon. :^(
First, check the fuse. Second, you may have just bent the socket parts, which you can probably fix with a little careful work. Third, run the voltage checks and the Forum will start de-bugging. If it comes to that, tell us if the filament lights when powered, and which pins were where when the accident occurred - I am thinking that the filament (large pins) makes a good short circuit for the high voltage, so which pins were "shorted" together?
The original 300B has a small pin on the side of the base, which mates with a special bayonet socket, so that this can't happen. It never caught on, you can't find those sockets anymore, and nobody else has the side pin anyhow. Too bad.