The Blister's are actually from discoid Lupus...which causes the trouble for the skin but secondary is just as bad and like your son...i had the steriod creams which worked great but my skin won't work with them now but my DNA would work with the Dapsone and i get them up my arms i did a blog showing my arm best i could hands/neck/face and what kicks them off more than anything is heat rays from the sun, just sitting in shade will do it, i'm banned with my dermo not to go outside and sitting in the shade after 10mins triggers them and even though your sons inside just humidity heat in the air can cause it.
If it's warm where you are try and keep a fan going by him to keep his skin cool.
My blisters do come in the same spots but i have the odd occassion where they'll break out on my feet and then it's using steriod plasters to clear those up, incase of ulceration. The crying could be coming from being fedup with it because it's alot for a child but like i said Lupus can cause depression, it gave me manic depression from a teenager so just watch your son, as depression is like a ping pong ball in and out of your system like mad.
My first symptoms started at 5yrs of age i was always freezing cold and my eyes dark underneath, so my mom got me checked out for anaemia and apparentley i was ok and i went for years like that even in the summer and when i was 14yrs old i started having autisum and i do things i had'nt got a clue i'd done and then at 18yrs old depression kicked in bad and 2 forms of seizures then strokes besides other issues, the coldness was the raynauds and within the last 3yrs the lupus is strong in my blood besides the sjogrens disease.
See your sons young and is already getting fedup with it and seeing the doctor and i've had this lot going on for 25yrs from 18
till now at 42 and it's never ending appointments it just gets you down.
Hugszzzzz to you both and i don't mind you asking me anything, that's what we're all here for to give full love and support.