If there is data on the drive that you cannot afford to lose, then do not try to fix the drive yourself. I would also suggest that you do not even try to power it back on after it has been dropped, as this is what usually causes the most damage. Whether your drive is an external desktop drive or a small portable one, they all work in the same way. Broadly speaking the inside of a hard drive is a bit like a record player with a mechanical moving needle reading the vinyl record. I can remember the times when playing old vinyl records, once you got scratches on them they never really worked the same again.
So I recommend not to panic, decide on what the value of the lost data is to you. Sometimes it may not be money value but a sentimental one. Once you have decided, then carry out some research online and look at data recovery company reviews. From our experience with dropped drives, the amount of work involved in overcoming the problem would not be covered by the low initial cost that some data recovery companies advertise and therefore the cost would soon escalate.
There is always hope of recovering data from a dropped drive but as you have read, it depends on your actions as to the eventual outcome.