My DS had this last year and the Dr told me it would take 6 to 12 months to clear up. I got rid of it in three weeks doing the following:
Daily wash with Boots Tea Tree and wichhazel facial wash ( use on whole body)
Stopped using sponges and flannels in the bath/shower ( in fact I banned baths!)
Treated each spot with a tea tree and wichhazel cream morning and night
Squeezed any blisters that looked about to pop and covered with a plaster treated with tea tree /wichhazel cream ( did this morning and night)
Washed bedding every day ( a pain but worth it)
All towels used once only and then washed
Kept him off swimming for three weeks.
Doctor was amazed when I went back for a follow up appointment.
My DS has excema too but The above treatment caused no problems.
Hope you get it under control soon.