You may need to pay a technician at a store to help you.

If you want to do it yourself, there are many software products available online to try to see if data can be recovered from a USB hard drive, but I suspect from your question's wording that you woud have a difficult time learning how to do so. You have not stated the type of damage, or the kind of error messages you receive, so it is not easy to suggest anything other than paying a service to attempt to recover it for you.