After Keratin treatment what do you do to put curl and body back into it?

My hair is fine and thin but has enough natural curl that I normally can have fullness and style all day unless there is humidity. Then it goes limp on top, fuzzes on the sides and looks terrible. Just moved to the coast where humidity is a constant. Decided to try a Keratin treatment. Flat and straight is not a good look on thin fine hair. It has been a real struggle to get any body at all. I use WEN shampoo, always, I've been spraying while damp with Volume Solutions by Ion, but probably any volume booster will help. I blow dry with head upside down to get lift at roots. Use a smaller barrel on a curling iron than I had needed before Keratin. Then don't brush but just run finger lightly through to get style. Then have to use hairspray. Heading out to buy Shielo's Volume hairspray that had good reviews on line for holding in humidity without stickiness. Good luck. I probably won't do Keratin again.