One of the risks of any injectable medication is bruising (usually mild and very temporary).
If you are on a blood thinner, you will still see a nice effect with Botox
even if you have bruising. Bruising while on blood thinners
may last longer. I have performed 1000's of Botox injections and have found it is often possible to visualize the veins in the target areas and avoid them most of the time.