These pictures (not injected by me) shows how the vascular occlusion that occurred in @timestops4beauty 's top lip evolved (shared with her permission):
Top left is before the injection. Bottom right is how it is now with the scarring after the skin necrosis (skin death).
In my opinion sharing rare, but serious complications like these, is as important as sharing beautiful before and afters.
The circumstances around this injection shows that if you get injected on a Friday evening and the clinic is closed for the weekend, you need the contact information to your injector in case of situations like these. She ultimately got the filler dissolved but it was after 72 hours.
Complications may occur after any cosmetic procedure. The most dangerous ones are the vascular complications, where filler is (accidentally or because of lack of knowledge) injected in a blood vessel, which will in turn clot the blood vessel. This will result in reduced or no blood supply to the area that is dependent on that blood vessel. It may be a skin area, it may other areas like the retina (resulting in blindness).
Please remember that if you get injected with other fillers than hyaluronic acid (like permanent fillers), there is no way to dissolve it.