White lines showing up in PDF saving from AI

Hello,

I am working on a vector file in AI. When I saved it to PDF white lines appeared around some of the vectors. At first, I thought some of the colors were changed but when I zoomed in it looks as though the vector within the shape (the shapes fill) has tiny white lines around it like the vector shrunk.

I've attached images for reference. The first photo is the AI file zoomed in to see there are no white lines within the flower. The second screenshot is the zoomed-in pdf file of the same flower save from the AI file. It is hard to see unless you zoom in but if you look at the pdf the color looks completely wrong. 

here is an image not as zoomed in. 

You can see 4 flowers have those really light lines in them and you can see the stem of the flower behind them in the flower with the white lines. It is because I can see the stem through the flower that I think the vectors are shrinking creating a gap and allowing the background image to show through. I hope this makes sense.

Thank you so much to all who halp!

Jaci