Not blindingly, mirror-shatteringly ugly, not fat, or covered in acne (I have really good skin, actually) but you know, I shaved my hair for cancer and I look like I'm from the fifties with my current hair-cut. Plus, my face just isn't all that attractive.
Being a teenager is supposed to suck. In fact, the more it sucks the better later on. Trust me, the people who loved being a teenager are going to fall WAY behind in life. The trick is just getting through it and entering adulthood. When you get there mean are easier to find. But for now, count on it sucking from start to finish. Just study, make a few friends, find a hobby, and plan for the future.
Sorry you had cancer, that clearly adds a few levels to the story.
Honestly? I'd say sort of. Highschool is harsh. My guy friends would still be friends with certain girls. Then I remember the first time it started to change with some of them, suddenly they'd be taking more interests in certain girl and it's "because she got hot over the summer" Even for me I was rather plain until the end of grade 9 and suddenly I notice things starting to change.
get some hair extensions or improve your haircut. go to a nice salon and ask them to give you something that works with your face
wear makeup that emphasizes your best features. even if you don't think you're a beauty queen you still have positive features, don't think of yourself so negatively. having really good skin is a blessing, your probably prettier than you think
make sure your body is on point. most guys care way more about your body then your face anyway.