To regain access, it will require taking several steps:
Step one is to navigate directly to the Facebook login page on your phone and click "Forget Password?" Step two involves inputting both email address or phone number associated with your Facebook account as part of Step three and providing information that is specific to that particular Facebook profile, in this instance email or number associated with an existing one, so Facebook may issue you with either a reset link or verification code for password retrieval purposes.
Check your email or messages for the link or code to reset your password, then follow its instructions to do it. Having done that, you should now be able to login back into Facebook account with an updated one!