I am a 24 year old with facial PWS.
I would first recommend going to the resource section in the tool bar above and see if there is any doctors in your area you live in.
Second thing is on the front page of this website the is a doctor that specializes in KT. (in case you have not heard of KT it is a condition that happens often when PWS is on arms and legs). This could be one of the reasons for the pain in your leg. I would recommend sending this doctor a email with pictures discribing your problems.
Also, you could check out Dr. Levintin Ask the surgeon, or Dr. Nelson Ask the PWS expert about any additional questions you might have.
I hope this help.