How much head space did you have before fermentation? Maybe you should check to see if the head space has been reduced by the amount of water that was in your jar. Might also be hard to tell if it was a small jar, but I'm wondering if it did get sucked in somehow.
Two things to learn from this experience: 1) put the jar as low as you can. 2) use a cheap vodka in the blowoff jar. If it does get sucked back in, the only thing that will happen to your beer is a higher alcohol level.
I'm not sure what Starsan will do to your beer, but it might be a good idea to google. How much was in the jar?