lindsay,
Too bad it's getting worse.... :-/
I have only just signed up to the board, so I haven't had time to read everything yet, but here's what helps for my scalp:
I don't have experience with Daivonex Scalp Lotion (but I do with the Daivonex cream)
I use two different shampoo's which work great for me
1- Selsun
2- FreeDerm Zinc
If I have an outbreak (after not having used either of both for some time), the first couple of days I experience the same as you do.
I don't know why, but I think it "loosens" the scales, therefore "huge" scales appear as opposed to lillte flakes.
But generally after using the shampoo's for 2 weeks, that stage has passed and I'm on my way to a p free scalp....

But as with everything p, everybody reacts differently, so I can only say I hope it works for you

Good Luck & let us know....
PedroER