Do facial injections cause scar tissue?

Hi, whether fillers move or cause scar tissue depends on what type of filler was actually injected. Hyaluronic acid (HA) fillers mimic a substance that occurs natural in our skin, and so granulomatous reactions and scarring are very rare (but not impossible). Letting filler dissolve (6-18 months) before getting more injected is also a safe practice. Injections of liquid or industrial silicone or mineral oil, which should never be done, will almost certainly cause internal scarring that can be quite severe and debilitating, and can move to areas outside of the original injection site.