I am by no means an expert on CRPS but I do have it in my left hand/arm. I read as much as I can and have seen some references to bulging veins. I have also noticed that the veins on my injured hand are sometimes more prominent than on my right. I am sure there are many different things that could cause your issue but if you have the resources to contact a CRPS specialist than that would be my suggestion.
Hope you find the answers you need!! :hug: