Accidentally make all files uploaded as 9B octet/stream in firebase, is there anything i can do to recover it?

Question

I was using firebase storage to upload user pdf file, and tested that it successfully uploaded. But unfortunately, the files are saved as 9B octet stream not pdf. I found the solution to upload files as pdf, but haven't found any solution to recover the uploaded octet stream files back as pdf. Is there any possible way to convert the files back to pdf?

The firebase dashboard