I've found a way to make looks basically a non-issue:
First of all, if a guy just dresses and looks plain, with no sense of style or effort to look good, her "NOPE" switch will be immediately triggered. I'm not exaggerating here. You can actually see the up & down scan immediately followed by the flicking of the switch "NOPE".
But the good news is that we guys don't have to be all that good looking. Hear this carefully:
If a guy shows TOKEN effort in paying attention to appearance, that is enough for a woman and the "Looks" shut-off switch is bypassed.
It is always the simplest things. A little gel in the hair, an interesting necklace, basically anything that conveys "I was conscious of my appearance before walking out the door today" will do the trick.
My suggestion to the O.P. is to find one thing at a time to improve your appearance. It can be anything at all that conveys a consciousness of style. think about what you can do. Hair? Sunglasses? Clothing? Shoes? (BTW, women pay HUGE attention to shoes). Improvement products for complexion? Are you working out? You're just coming to the age where working out is advisable & beneficial.
Make some changes a little at a time and you will find that both men & women will have a new-found respect for you, because you will be domonstrating that you respect yourself.
You're only 15, and as most of the guys here said, things will likely change for the better for you. In the meantime, pay attention to the little things, and you will reap big rewards.
I'm very sorry that this one guy said what he said to you. I'm sure it stung like crazy, but it shows that he has serious issues. He is probably immensely insecure and needed to elevate himself at your expense, even if just in his own mind.
Hey, man, I used to think that I was the ugliest person in the world. It was only recently that I discovered that:
1) My self-assessment of my looks was exaggerated due to self-esteem issues.
2) Women keep you in play if you show a token attention to appearance.
There's plenty of hope for you. Even if what I say doesn't seem to make sense, I urge you to try it. You will feel a lot better about yourself. Remember, don't wish for good looks. Only pain can come from that. Instead, demonstrate to the world that you do the most with what you have. People respect that, and more importantly, you will respect yourself.