Hello, thank you for your question. The lips are highly vascular, meaning that many arteries and veins run through them and sometimes they are more visible on some people. So its absolutely fine to treat your lips with filler. An experienced injector will be able to examine and avoid the blood vessels as best as possible to decrease the chances of bruising. All the best,-Melody PAC
These blood vessels will not be a problem with regards to lip filler treatment. I recommend you see an experienced injector for best results. I prefer hyaluronic acid based fillers like Restylane and Restylane Silk when treating the lips. Good luck!