Hi there,
I fully understand your situation, I am 30 years old & I got my Psoriasis when I was 7 years old & have had it ever since, i have been through most of the difficulties with this skin condition from being thrown out of my first swimmimg lesson at 8 years old by the instructor because I was scaring the other kids to trying my best to hide my condition during my college years, i even used to wear fingerless gloves in summer to hide this from my college friends. Luckily all my friends thought the glove thing was cool and after the first term fingerless gloves were in fashion as half the college was wearing them!!
Then their was the girl thing & the hangups with getting into relationships, I have to admit still suffer from these same hangups but getting better.
Regards the blame game, i am the same as your son, on many occasions I have looked to blame or taken out my frustrations on my parents as my P is a very much an inherited strain, my father, mother , grandmother & my sister all have psoriasis to some degree!
As to support groups, the most amazing thing for my was my first trip to the Dead Sea when i was 15 years old, i was unsettled at school & ran away because of my insecurites with my skin, when my parents got hold of me they decided to ship me off to the Dead Sea & for the first time in my life I met fellow sufferers outside of my family & it was & still is the most liberating experiance i have had!!!
I go back quite often & this allows me the confidence to keep as grounded as possible & keep my skin in check.
I strongly reccomend giving it a try, some people go & get a great result & the P goes away for long periods or does not come back others go and get cleared up & have to return when the P comes back but either way it helps both with clearing up the P & psycologically.
If you need anymore info on Dead Sea let me know as a load of us are heading out there again in April.
And as Heli & mattellie said the DS enviroment cannot really be replicated
You can always try support groups but my advice is to talk to other sufferers. Like on this forum.
PS People always tend to take out frustrations & apportion blame when they are in this type of situation but they only do it to people they trust & love so take strength from this, so however bad you feel try & keep you chin up as however tough it seems you are the rock for your son & his shoulder to lean on & you are doing a fantastic job

PPS Sorry if a waffled a bit too much
Cheers Gareth