It depends on how it was damaged. It should not have too much pressure. I wouldn't get my hopes up however there is some spray on rubber sealer that I have seen on TV that if applied correctly may seal it. That said I would just have the tank replaced.
2004 Chevrolet Silverado 3500 LT with a 2004 Jayco JayFlight 29BHS
2014 Greyhawk 31FS with a 2007 Tahoe toad
2014 Thor Palazzo 33.3 with a 2007 Tahoe toad