On the outside, the shaft may look fine. On the inside, it could be fractured. On the other hand, you may not damage it at all. The best solution is to treat graphite shafts as you would your children - tenderly, with love and affection. Many of today's golfers grew up with steel shafts, which are golf's answer to the indestructible force.
Steel can withstand all kinds of abuse.
Graphite, however, requires a new attitude. Back then, with a persimmon head and steel shaft, you could throw a driver off the back of a truck at 50 miles an hour and you'd have a few dents in the head. Otherwise, you were fine. Well, that is debatable. Graphite is uni-directional.