It is a common concern or question from patients whether filler can migrate or not. Essentially the answer is theoretically yes it can but practically speaking wise it does not. Every filler company makes various filler products for different areas of the face - the hyaluronic acid particles have various manufactured characteristics but are still just hyaluronic acid. These differences pertain to elasticity, viscosity, rigidity, and how much they attract water. For chin filler I like to choose a rigid highly form stable filler material that does not absorb water. I inject this deep in the tissues just in front of the bone. You want a firm rigid filler in this region unlike what you want in the lips which needs to move, be soft, feel flexible etc. The irony is that the more flexible and soft the filler is, the more it is easily sheared away by movement and lasts less time. I expect chin filler to last at least one year if not a bit more you can feel free to redo it at any time you feel you need more volume replaced to that area. For restrictions afterwards I recommend no heavy workout for the day, do not press on the area, no alcohol that day, ice for bruising, I give my patients Arnica as well that helps with swelling. You can expect some swelling and bruising that lasts for a handful of days but should easily subside.
Yes you can have Botox treatment with prominent facial and forehead veins. The vascular anatomy in the face is similar amongst all patients. However, due to body habitus; skin thickness; skin color; and other factors some patients demonstrate forehead veins more prominently than others. Botox treatment and injections are mildly uncomfortable and bleeding is fairly minimal. It is up to the injector's technique to visually appreciate any prominent veins and to not inject directly in the area. However, if this were to happen injecting a minuscule amount of Botox into a superficial vein is of no consequence. Any bleeding that would result resolves with holding a gauze pad over the injection site with moderate pressure for a minute or two.