You just have to be very, very patient and resist the urge to "see how he looks". The horse should be on stall rest, and wrapped. Back on Track wraps might be a good thing to invest in as they have sped up injury healing time for people and horses I know. You can also do IR laser therapy and therapeutic ultra-sound to help speed healing.
Other than that it is basically walking in straight lines with no sharp turns, and especially no lunging. Do not lunge this horse ever again if at all possible, and especially not within a year from now or when he is unfit.
Depending on what the vet says (and ultrasounds are usually the best way to tell when the injury is healing) I would start hand walking in straight lines for 10 minutes twice a day after another 2-4 weeks of stall rest on soft ground (ie not concrete, but not deep footing, grass or something would be good as long as it isn't slippery). Then gradually increase the time and when it is pretty much healed, start walking on hard surfaces to strengthen the suspensory and start trotting in hand as well. Then change to undersaddle and avoid deep footing, small circles and lateral movement.
If you've caught the injury early there is a high chance of it healing well and never giving you grief again, but you have to be very patient and diligent and give it time to heal and strengthen. Condition the horse back into work properly and don't lunge.
They say money doesn't buy happiness -- well happiness doesn't buy horses!