Colour versus volume
Filler is a gel injected into or around the lip body to add fullness, project the lip, or define the vermilion border and cupid's bow structurally. It is not a tattoo and involves no pigment.
Lip blushing adds no volume. What it can do is make a lip look fuller by darkening the body slightly, sharpening the border and placing a subtle highlight illusion — but the lip itself is the same size.
Timing if you want both
Most artists ask for at least four weeks between filler and a lip tattoo, in either order, and often longer. Fresh filler means swelling and distorted anatomy, which makes accurate mapping impossible; fresh tattoo means an open wound you do not want a needle injected near.
A common sequence is filler first, let it settle a month or more, then blush to the settled shape.
Choosing between them
If your complaint is 'my lips look pale, undefined or asymmetric in colour', blushing is the tool. If it is 'my lips are thin and I want them bigger', that is filler. Many people ultimately do a little of both.
