I also would recommend seeing a specialist in vascular birthmarks. You can use this website to email one of the specialists and get an opinion about what should be done. I agree that with so many superficialy, there is a chance of having internal ones as well. This is something that would only be picked up through a specialized study. Please don't wait and see. So many pediatricians recommend that but they really are not up to date on treatment options. Our pediatrician is a good friend of mine and she was very surprised to find that they are treating hemangiomas now, and was not aware of seeing a specialist for further studies if your child has multiple ones.
Good luck! Please update us on how things are going.