Is the film exposed or unexposed?
If you have accidentaly wound the film back into the can when it is unexposed - the only way you can sort it without a retrieval tool is to get a re-useable cassette. In total darkness carefully crack open the film cassette and transfer the film to the re-useable, making sure you get the film in the right way round.
My advice would be to move heaven and earth to get a retrieval tool. Worth their weight in gold.
If the film is exposed - then you don't need to retrieve the leader. Just crack open the cassette in the dark and load it on to your spiral for processing.