Not sure if I understand the situation correctly...
Do you see "bad sectors" reported by Hard Disk Sentinel?
If so, you do not need to worry about those bad sectors as these are already fixed by the hard disk: now the disk uses the spare area instead of these bad sectors, all read and write operations are using the spare area. This is called "reallocation".
This means that (depending on the actual number of bad sectors and the health level) you may still use the hard disk for storage.
However, if the health is low (the number of bad sectors is high) then there may be further reallocations possible, which may lead to data corruption / data loss and cause system instability.
So having high number of reallocated sectors can be risky.
I recommend to read the proper sections of the Frequently Asked Questions page:
These describe the recommended steps to analyse the hard disks, reveal and fix any possible issues because the most important is to verify if the drive is stable (there are no more, currently hidden problems).
If the tests show no errors (which means the hard disk is now stable, all possible bad sectors are already re-allocated and fixed this way), it is possible to acknowledge the reported problems and remove them from the text description, to improve the health back to even 100% as then the software will only report future issues (if there will be).
This is described at http://www.hdsentinel.com/faq_repair_hard_disk_drive.php
If you use Report -> Send test report to developer option, I can check the actual situation and may advise about the hard disk and the recommended ways to diagnose / repair (if possible).