Abstract: Described herein is a disposable drug delivery device and system (e.g. a hormone replacement drug in the device), and methods for administering precise, metered doses of topical and transdermal drugs to a user's skin. The device comprises: an overcap; a dispensing cap with at least one hole; a barrel that holds the drug; a threaded spindle centered within the barrel, and connected to a platform that moves upward through the barrel to push the drug out of the hole(s); a bi-directional reset dial that is not connected to the platform, to mark the starting-stopping point; and a unidirectional dosing knob that is connected to the platform, with markings for sequential increments of drug dispensing (e.g. 0.1 ml-0.9 ml drug/actuation). Due to the reset dial, a user is not required to keep count of their dosing knob actuations to know when they have dispensed the entire dose.