Importing fbx from blender 2.8 to unity weird looking mesh

So I am pretty new with blender and I made a tutorial from brackeys(unity “teacher” in youtube), and even imported into unity and it all worked fine. But I tried to make my terrain in blender and then import it and it looks so weird, and I have no idea why. I am not sure if the question should be posted here or in the blender forums, so I will post it here first.

This is how the terrain looks in blender:

When I export it it as .fbx this is out it looks in unity:

You can see a bit of the grey color on the mountains which is weird too. Things you might need to know is that I didn’t add/bake any texture, it is just the colors. What am I doing wrong ?
Thanks in advance

I found the answer, the textures were inside out! So I just selected everything and press Cntr-F.