Im trying to scale the edges along a curved surface. When I do the method scale and X, it scales with no problem, but when I try to scale along the Y axis, it distorts the face, the edges dont scale proportional
Creating custom orientations will help you in many situations where you have to move or scale many faces/edges/vertices along directions that are off the usual orientations.
However, if you only have one face like the one in your screenshot it is a bit easier. And if you have multiple ones pointing in different directions, creating a custom orientation for each of them might be very uncomfortable.
Instead you can select the face and set the orientation to Normal (which would also be used if you created a custom orientation) and then scale along the face normal's X or Y axis with simply using S > X (or Y). You don't have to press the key for the axis twice - that will use Global orientation.
It's only important that you use the face selection instead of only selecting the opposing edges you want to scale, because this might result in an unwanted orientation (see picture on the left).
Your mesh is not aligned with global coordinates, so X, which is quite aligned, works quite well, while Y, which is not aligned at all, works very badly.
To solve you can create a custom transform orientation: select the center face of the zone to be scaled, go to the transform menu and press the + icon, creating a transform orientation aligned with the selected face's normal.
Use this new transform orientation to scale as you want (S, Y, or S, X).
When working with curved surfaces is a good habit to create a copy of the surface with regular geometry (without insetted faces) and use it with snap to face or shrinkwrap modifier to project the insetted vertices exactly on the curved surface, in order to get the best possible shading.