Potentially, Neptune can create a beautiful person. But Neptune can only create beauty if it's found in the 1st house or aspect to someone's personal planet. And Neptune's beauty is different because it usually refines or distances the person from who they really are when people look at them. At least, that's what I think.
Neptune in the 1st can add some of the same characteristics as a Pisces Rising native. Neptune doesn't "refine" it's actually the opposite -it
dissolves whatever it touches-- it blurs boundaries. A 1st house Neptune can be vague, evasive, "foggy", "soft" or "rounded", polymorphic or "shapeshifting". They can change looks and seem different to others through various moods and phases, depending on the sign.
On the ASC or in the 1st, I can see this planet projecting a more spiritual, "soul beauty" felt on the etheric plane I suppose, but that depends on the native pursuing the higher, more positive octave of the planet (as opposed to addiction, delusion, etc.), and where they are in their own evolution.