I also have the PWS on left arm and hand. This was extremely painful during puberty as the birthmark was growing faster then the rest of me. I would have to go to the girls room to cool off the heated patch. My PWS is my mood detector, it lets other know what mood I am in depending on the colour. If I am upset or mad it is dark red, if I am passive it is pail pink. One of the things as an adult that I do not like it that I currently have anxiety and the left side "feels" everything more intensely then the rest of me, which makes me think I am having a heart issue. With the birthmark being on a arm it will throw off your balance as area to which the PWS covers is larger from puberty, so simple things like biking or body support can leave your shoulders sore. Exposure to sun leaves it irritated and redder until the burn heals, please do not expose to long periods of sunlight. I have worked with kids for over a decade and have had many a questions concerning my spotted arm and hand and I have smiles with them and they touch it and move to watch it disappear. I was bullied in school because of it, but I survived. I actually get mad at people who cover their birthmarks as I feel that everyone needs to see it to accept it. It belongs to me, it was free and it makes then unique from others.
As a kid, I would outline the patched in boredom, hours of entertainment. My mother was good, she explained to me what it was and it was good because I could always tell my right from my left with the spots. It was a free tattoo where others had to pay for theirs, and that it made me special. I am glad she did nothing to cover it up. My good friends do not see it, strangers do and I forget when they stare why they are staring and just smile at them. I ware tank tops, I do not cover it.
I call my birthmark my mood detector, it on a normal day feels like there is a glove over it, so I can't check water temp with it. If I am out of sorts it can be painful until to reason goes away. Pictures, I have a tendency to put that arm behind my back so the flash does not zone into it. Other then that it is just a birthmark.. a free tattoo..
I am open to questions, I have lived with this for 40+ years