If your Apple Pencil has been dropped onto a hard surface, despite having no visible physical damage the Pencil, the Pencil may have suffered internal [shock] damage from the impact. The tip transducer is a fragile component - and despite appearing to be intact, may have suffered irreversible damage.
Here is one of the better troubleshooting guides - which may help with troubleshooting:
https://appletoolbox.com/apple-pencil-not-working-heres-our-troubleshooting-guide/
If you are able, try testing the Pencil with another iPad. If the Pencil pairs - but is otherwise unresponsive - you will have confirmed that the Pencil itself has been damaged.
Alternatively, you might visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess both your Pencil and iPad:
Genius Bar Reservation and Apple Support Options - Apple