Why does some filler end up above my lip and outside the lip line, even though it's injected in the wet/dry border?

When I get juv. UP in my lips why does some of the filler end up above the lip and right outside the lip line, even though she injects in the wet/dry border. It’s like it migrates upward.I’ve also been getting less every time (less than a syringe). Could it be b/c She’s not massaging hard enough? (She barely massages after because there are never any lumps) or b/c she uses a micro-cannula? (Wonder if it stays put more with a regular needle). Do you recommend injecting even lower down on the lip