1)Start treating it ASAP.
I read about some recent research done on the mechanism of concussions, and basically it suggests that loads of antioxidants and anti-inflammatory chemicals (including fish oil) can significantly reduce damage if given very early on.
I only started treating (supplements, rest) it after 3-4 days .

2) The symptoms might seem relatively mild at the beginning, but that doesn't mean they'll be over soon.
You may be lucky and make an early recovery, but if you're not doing so bad right after the injury (I wasn't--I was basically feeling like I was hungover and that's about it) that doesn't mean you'll be out of it soon. I wasn't even unconscious and I'm still battling symptoms 2 months later. A friend of mine was knocked unconscious once, and became symptom-free within a week.