Is there any way to process Oracle BLOBS being converted to HEXDUMPS in database reader node? I don't think that they are entirely the same as blob exported via SQL Developer is very different from the one copied from the node.
However, if you planning to execute this in KNIME's Database node you must ensure that each statement (within one row of the script) can be executed as a JDBC command, for example PL/SQL with its keywords such as END / BEGIN won't work that way, see here for further details.
The Database nodes support BLOBs which can also be "manipulated" using the File Handling package available at KNIME Labs on the standard KNIME update site.