riddle - Sometimes I'm ugly, sometimes I'm art. What am I?

Sometimes I'm ugly, sometimes I'm art,

Sometimes I'm near and dear to your heart,
I have been known to bring about pain,
And yet I deliver relief just the same,
You know where I live, yes you know it best,
For I am not hidden like all of the rest.

What am I?

Hint #1

I come from a family where we each have a twin,
Even when we're well nourished, we always stay thin

Answer

NEW GUESS

I think you're a

fingernail

Sometimes I'm ugly, sometimes I'm art,

Sometimes people let their nails get out of hand, other times they get them painted.

Sometimes I'm near and dear to your heart,

People move their hands, bringing their nails close to their heart.

I have been known to bring about pain,

Nails can scratch.

And yet I deliver relief just the same,

Nails can scratch (itches).

You know where I live, yes you know it best,

You know where your fingernails are...

For I am not hidden like all of the rest.

Fingernails aren't hidden like the rest of your 'bones' toenails.

I come from a family where we each have a twin,

We have two hands, and so we have two of each 'kind' of finger.

Even when we're well nourished, we always stay thin

Fingernails don't get fat, even when we're well fed. They just elongate.

PREVIOUS GUESS

Poem