Do you really think that Boeing would invest billions developing the aircraft, and the airlines would order hundreds of them, if repair-ability hadn't been thought of?
In the first instance, the hull is less prone to damage as it is harder that conventional aluminum structure.
Secondly, a repair regime is part of the package. For a normal type of "ding" such as running a baggage loader into the hull might cause, a patch can be applied that takes 30 minutes to repair and lasts five years.
A major hull damage can be repair on an overnight service and is good until the next full strip down (about equivalent to a "D" check, but at longer intervals.)
Repairablility and therefore avoiding down time is actually one of the (many!) things that is making the 787 a revolution in the industry.