Well the good news is there is so much new technology these days rather then when I was young. You have got an early start on your sons condition which is very commendable. My mother didn't start trying to find treatment options until I was about 7 years oldd Most likely it was because there really wasn't much of an option. Doctors said sit back and wait and see what happens and then one doctor told me I only had 6 months to live so to make th most out of it. The fact is that they really have learned a lot in the last 10-15 years about this condition. Of course, your sons case is a little different then mine. I have a very large VM (hemangioma) that goes from my lower left leg and all the way up into my stomach. Although it is not the same as a port wine stain, the area your son has his birthmark in is a lot like the area mine is in. I recently had a pelvic exam and they found that it is starting to invade my rectum (which is causing serious bleeding) and the pelvic exam was almost unbearable due to the fact that they think the tumor is beginning to be in my private area. The Pel Xam was so painful I nearly threw up. Anyways, As for protection, I don't know if it's the same w/ port wine and hemangiomas but I was always told I had to be careful not to puncture the area of my birthmark because there is a chance I could bleed to death from just a small lesion to any part of the Bruised region of the birthmark. I am not sure about the sun or if it has any effect on these types of birthmarks. I am currently seeing a radiation oncologist and they seem to know more about my condition then anyone so far so thats what I reccomend. Good luck w/ everything!