Like you, I was on MTX for psoriasis and PsA until I ran into problems, in my case liver enzymes. And like you, I ended up on Humira, which I've been on for two months.
On MTX, I had no psoriasis at all, but I did have consistent problems with yeast and fungus. When I started Humira, I had been off MTX for 3 months and my psoriasis was getting steadily worse. Then after my first dose of Humira, my psoriasis flared dramatically. It was also my first ever bout of pustular psoriasis, which is just as nasty as it sounds. My dermatologist declared this a coincidence, unrelated to Humira. She gave me a new (to me) topical, ProTopic, which worked very quickly, despite not having a steroid.
After two months, I think I'm making good progress on the joint pain with Humira, but the psoriasis doesnt seem to be improving as much. MTX cleared my psoriasis in just a few weeks. For me, biologic therapy works more slowly than MTX, but I haven't had any side effects from it, while MTX caused some real problems for me. I'm still very hopeful about the Humira.
Healing well with psoriasis, PsA, and hypogonadism, and happy to share my experiences.