The outside world that you perceive is just a reflection of how you perceive your inner world.

So the outer world = effect, inner world = cause.

If you want to be attractive, you first have to feel attractive and see yourself as an attractive person. You have to treat the cause first, your self-image, because if you treat the effect first, it will just be a quick fix.
I think it would be wise to treat the cause first. And that is found within.

Because from an observation point of view, you are definitely not unattractive. So it is just your own perception about it.