It's more social events that I've missed out on because of acne in the past. Though I've definitely had times where I haven't wanted to go to uni because of my skin. Especially when I was taking anatomy and had to spend a lot of time in the labs - the lighting in there was terrible for showing up all my acne / PIH. But I just had to get on with it - even if it meant I sometimes felt pretty shitty and wanted to hide. But I've been lucky to meet some great people and make great friends at uni and I always have a good time when with them so I don't even think about my skin then. And having classes / assignments can be a good distraction from your skin too. The less time you spend worrying / obsessing over your skin the better!
In lectures people aren't going to see your acne anyway really - often the lights are dimmed and everyone is facing forward / focusing on the lecture and aren't going to be looking at your skin / caring about it at all
Try and get back into going to the lectures! It's better than causing yourself stress trying to catch up on all the material later / when exams are around the corner!
Lol, I always hated labs because of skin and students tend to be selfish. Just because I am quiet, they think I don't want to do anything? They should at least offer... A kind person would offer someone if they wanna do something. Apparently they aren't nice so I don't care. I will let them do all the work.