I not tried exposure therapy, but have been forced by life into exposure to many things.
I spent 10 years as a waitress at Denny's. It did not cure my problems, but it did force me to aquire skills. In between I had more than 30 other jobs that I always quit within a month because I would get all paranoid about someone or other or something, but I did not want to burn my bridge at Denny's because once I got out of the house I needed to pay my bills.
My mom worked there and I had known all the older workers since I was a small child, so I had a pre-built nitch there. It was very, very bad at times, public panic attacks on a regular basis and such. I did learn how to look at someone and smile and listen attentively and act happy about it. I am slightly chipper, and efficient in my professional mode, and as long as no one tries to talk to me more than business or joke or laugh I do quite well.
When I was about 25 I married a man who speaks almost no English and later found out he had problems with immigration, and major credit problems. Since I spoke English it was me who had to speak to angry creditors who we could not pay. I also dealt with numerous not so nice immigration folks, and was a temporary single mom when he was in Guatemala for 17 months. This did not cure my fear of talking on the phone, or confronting things, but now I know how.
I think this is why there are so many younger people with SP, because once you have to start making your own way, you get a lot more exposure to things, because you have to. You learn new skills as you age.
Now I am a CNA (nurses assistant) and I am completely amazed at what bad communicators some of my coworkers are. They could solve so many problems by just communicating better with their residents. All my waitress skills are still with me. I may not have any friends, and I am physically unable to laugh and joke with my bosses but I can communicate better than average. I am Very proud of that.