I have psoriatic arthritis. The psoriasis is not that pronounced in %, but my head is pretty visible. It
sucks to have it. Going on 32 years now.
I used to use Dovenex cream until my insurance company decided it was too expensive. I think it's over the counter in Canada for about $125 last I checked. The replacement is Calcipotriene cream. I liked the Dovenex better (it was easier to pronounce, too!), but the other seems to work ok so I haven't tried Canada yet. It's just a pain to grease up once or twice daily (make fun of us sick people here). I haven't noticed any real side effects from these topicals.
I'm also on Methotrexate for my arthritis, which is supposed to help some with psoriasis, but I never noticed it doing much except with the pain. I did get really sensitive to the sun one year and burned quicker than normal, but that doesn't seem to be an issue now. It is one of those drugs that's hard on the liver (it is a chemotherapy drug), so I have to have periodic blood tests to make sure it's ok. It also can suppress the immune system a bit, but it doesn't seem to do that too much.
I'm staying away from the stuff that destroys the immune system right now because I don't think I'm bad enough to take that risk, but I've heard good results have come from that. I also don't like to jump on the newest drug out there because those folks are just the Guinea pigs.
There's good info at
https://www.psoriasis.org/ if you haven't been there yet.