hi im new to blender and i want to know if i can paint in different color both side of this faces without using any shader, i tried uv unwraping but always when i paint one side of the face the other is painted too this is the object im trying to paint.
You can't unwrap differently for a simple material, but you can use a Geometry shader node to select different colors for each side of the face. Here's a very simple example:
On an open cylinder this will make the inside of the cylinder orange and the outside blue:
Now you can use the same UV Map but drive Color1, the outside, with an image texture that you painted. You can then either use a simple color for Color2, the inside, or the same UV map with a different image, or, I suppose a different UV Map with a different image texture. The material for the last case would look like this: