Hello @Pernicio and welcome 
A node can be recovered even if all databases were to be lost, but on the other hand you should not delete any stored data files: this could lead to disqualification.
If only some db files are lost, here is how they can be recreated:
In last resort if everything else fails, deleting all database files should work, but you would lose all statistics for current month, and possibly some of your earnings for current month also, but at least the node would be “saved”.