YOU ARE GOD'S WORK OF ART
Outwardly, you may not appear to be much of a masterpiece. You may look like a piece of junk. But inwardly, and in reality, you are God's work of art -- and God does not make any junk. All that is outward and seen is only temporary -- like the cocoon the butterfly inhabits for only a short time. So, while you should take care of your present body, don't be overly concerned about it. Most importantly, don't think of yourself as just the body you are now living in. You are a child of Almighty God, creator and ruler of the universe. Someone God is "raising" to be His companion for eternity. You are NOT insignificant.
Admittedly, you are a work in progress. God still has more work to do with you -- but He is the artist, and He will finish His work.
(Hint: As you submit to God, the easier it is for Him to change you into the wonderful image he has in mind. Someday, everyone will clearly see what God has done in you: making you a wonderful, unique individual worthy of Himself.
What is it that makes a person beautiful? If you have not thought about it, here are some reasons.
Youth: Everyone always looks their best when they are young. Obviously, the younger one is, the better they look. Yet those who are "young at heart" - full of happiness, full of feeling a sense of wonder and adventure about the world, of child-like (not childish) happiness, etc - always project a more beautiful appearance.
Kindness: Those who are full of loving kindness, those who are positive, those who are always ready to lend a helping hand, acquire a "filter" that projects the beauty (or the ugliness) of their soul. You can prove this to yourself by thinking about a person you thought was unattractive, at first, but, as you got to know them, became more attractive because you came to like them. Or, think about a person you thought was very attractive, at first, but seemed to grow uglier as you came to dislike them as you got to know them.
Thoughts: Those who "believe" that they are beautiful - in the deepest recesses of their heart and soul - tend to act on that belief by projecting it and so they tend to be viewed as more beautiful. Ask the most beautiful person you know in real life what they think about their appearance. Even though they will be quick to point out the flaws in their appearance, they will also be quick to say that they are, in fact, beautiful.
Action: Most people on Earth try their best to make their "bag of skin” as attractive as possible. Some spend small fortunes in getting surgery to make themselves "look" better (although after multiple surgeries others would question if that was the result). Yet, what makes a person beautiful is their "acting as if" they are... and doing the best they can with what they have. So if you want to seem beautiful, start acting-projecting beauty.