No pump, no gravity
The lymphatic system has no heart. It moves on muscle contraction, breathing and pressure changes, which is why eight hours horizontal and still leaves fluid sitting in the face by morning.
Add salt or alcohol the night before and there is more fluid to sit. That is the whole mechanism. It is not toxins, and nothing is being flushed.
What manual drainage does
It opens the drains at the clavicle and neck first, then moves fluid toward them in sequence. Light pressure, skin level, no oil. The change is visible the same day and holds for a couple of days.
Weekly for six weeks if you are chasing a real change; a single session two days before something that matters if you are not.
The honest limit
Drainage moves fluid. It does not remove fat, and it does not change bone. If your jawline is soft because of fat distribution, a lymphatic series will make it look better on the day and no different in a month.
Anyone who tells you otherwise is selling a package.