We have had two treatments. Our daughter is now 1 year old and her third treatment is due in April end. We have not seen any significant lightning. There is some on few areas but most of her PWS is still as it was. Like you we are also waiting to see some good results. I have read some very good results from few members though. It depends on PWS as every PWS is different. 20 days is a short interval, you need to wait for 2 months to see the maximum results.