"...he is completely different than he's ever been."
Sometimes a vet visit with an experienced herp vet is just mandatory.
Since this is such a radical change, without precedent, then there could well be some kind of physical sickness that's putting him in severe pain. He needs an x-ray to check his body for foreign objects like pins, coins, button batteries, etc.
He also needs a blood test to check his metabolism and white blood cell counts. Elevated WBC are usually caused by infections. Blood tests check several important metabolic functions, so they are a good value.
A healthy iguana can easily go for 6 weeks and more without eating. Maybe Charlie never fully recovered from last season's stresses, and now has to enter this breeding season with a deficit.
His skinniness did not happen recently since it takes many months for major changes to slowly unfold. IMO he was too skinny during last year's breeding season, and it's getting worse now.
His snout bashing has to stop. It can crush his snout bones, leading to severe sinus infections. Use some kind of semi-stiff foam, like backpacker's 1/2 inch foam pad. Cover all the surfaces he can snout-bash on. It's much less important for him to be able to see out of his enclosure, than it is for him stop the destruction of his snout. You can fasten foam to glass and wire surfaces with double sided tape, or hot-melt glue. That will change the temperature of his habitat so you may need to make adjustments.
Hope this helps.