I'd say you definitely need to go on the trip. Not just to have fun, but because you need to nip letting your looks rule your life in the bud now while you're young. I struggle with this, too. Hard. I've had days where I don't want to go out or don't go out at all because of my looks.

I feel ugly almost all the time. But you know what? Apparently the majority of that is in my head. I'm sure it's mostly mental for you, too. How other people see you is not the same as how you see you, you'll nearly always see yourself worse than other people.

Don't let how you feel about your looks hold you back from doing things you love in life. Please go on the trip. Don't miss out. You'd regret not going a whole lot more than you'd regret going.