No, Facebook does not log out of all devices when you change your password. While changing your password, you are given the option to log out of all active sessions, which will log you out of any device or computer that you're currently signed into. Otherwise, changing your password only affects your account's security going forward and is not retroactive. Therefore, if someone else has access to your account on a device or computer that you're unaware of, they will not be automatically logged out when you change your password. It's a good practice to regularly review the devices and sessions that are currently signed into your account to ensure your account is secure and logged out of any unauthorized sessions.