Retin-A (Tretinoin) or Differin?

I have some acne issues and school is starting in about 2 weeks. I know the gels aren't going to clear up my face by then, but i did read that they do exacerbate the acne and cause some more pimples in the first few weeks (thought you're still suppose to continue treatment). However, i really don't want a bunch of pimples on my face during the first weeks of school, so i was wondering which gel caused less irritation? And if you had any experience with either medication, did you acne worsen that much during the first few weeks? I know that with continued usage, the acne will likely to improve and deminish in about 2 months, but i just want to know how the bad the first few weeks are so i can know whether to start using it right now or not. Like I said, i'm starting high school in a couple weeks, and you know how first impressions are :) Thank you!