A chiropractor is GREAT with sprains & twists.
Our chiro is great with kids and has helped my son here and there since infancy. I firmly believe they are better at sprains than traditional doctors. The reason is that they set the ankle and ligaments in the proper position so that as it heals it is healing straight. Keeping a bent ligament wrapped will have it healing in an awkward position, much weaker than original. We have had more than one bad sprain/twist heal with no re-injuries. On the other hand, we have a friend who had her ankle looked at by a doctor and it has resprained off and on.
If you're still here, a minor injury would be only one visit. If it was more involved, your son would get the care it needed. I've also had the chiro check and not charge when everything was good.
You are a good mama for being so proactive!