This is a general post I wrote up for it:
Basically, what you do with AC joint is rest, massage the muscles around the area to increase blood flow for healing + keep the muscles from tightening up, fish oil for anti-inflammatory, ice if it helps. + non-painful mobility work
Once it start feeling better improve range of motion with non-painful movement, and start strengthening rotator cuff muscles to make the shoulder more stable.
Then work slowly back into compound movements.
Usually each of these steps will take 2-4 weeks each. Can take more or less depending on how your body recovers -- to improve recovery capacity take the fish oil, sleep more, eat quality foods, etc.
Let me know if you need anymore details.
2-4 weeks was if it was a grade 2 or 3.... maybe 1-2 weeks if it's a minor grade sprain for each stage. Depends on how fast it heals though -- some people have worse blood flow to shoulders than others.
Obviously, information off the Internet is at your own risk...