Uni can be a great place to boost your confidence and meet new people if you give it a chance. There are people from all over the world with a variety of appearances, and what you find (mostly) is that people don't pay much attention to those type of physical appearances when making friends, and if they do then they're most likely the type of person you wouldn't want to be friends with anyway. I was shy and quiet when I started uni, entirely did not think I would make any friends, and didn't go clubbing at all, but I did make friends that I still see now having graduated whilst also keeping my old friendships from school. Presentations and group work was tricky at first for someone like me who gets shaky in front of crowds, but practice really does make perfect and I got more comfortable and realised that we are all feeling the same way. I wouldn't shy away from a chance to study and further your knowledge and gain new qualifications if that's what you want because of worry over acne and being shy.