Plesk mysql database "psa" lost!

[sunroof]

I upgraded MySQL from 3 to 4, and I lost only Plesk database "psa". Everything else is fine.

Is there any chance I could retrieve "psa" database. Does Plesk backup that database?

Or, should install new plesk? Is it possible without losing any current data and/or configuration?

My server has CentOs3 with plesk 7.5.

Thanks