Are there any products to help hair lay flat?

I went to the salon to get the ends of my hair trimmed but instead the barber thinned out my hair. I have shoulder-length wavy hair and is prone to humidity. The bulk of my hair helps it to lay flat but now, after it's been thinned out, clumps of wavy hair stick out in all different directions like I stuck my finger in a light socket. I used to use leave-in conditioner to help with frizz and that worked, but doesn't seem to work now.
Anyone know of a product I can use to help my hair to lay flat while I wait for however many months it'll take for the hair to fill back in? Thanks for any suggestions.