Hii I just got a keratin treatment to straighten my hair from wavy to straight. I washed them after 2 days but will they look better?

So I kept the keratin in my hair for 2 days before washing it, and when I finally did wash my hair they looked very flat and straight.

Right now my hair feels completely flat and also stiff, and they pretty much look stuck to my head.

I’m honestly considering buzzing it all off because I hate how it looks, but should I just keep waiting? Will the hair eventually look less stiff and regain some of its volume after a few washes?

I would massively appreciate some response thank you for reading.