This area is usually the first to get battered during fights between males or during mating behaviour. If it becomes loose or flaky, keep it very clean and separate the animals for a while. More serious shell injuries caused by dropping or crushing need urgent veterinary attention. We see tortoises regularly which have suffered sometimes quite horrendous carapace injuries as a result of accidents with lawnmowers and similar garden machinery - this sort of accident could be prevented with a little more care on the part of owners. If the worst should happen, the severity of the injury will need to be expertly assessed - although it is important not to panic and be too dismayed by something that might look far worse than it actually is.
Tortoises can recover from some pretty spectacular damage given good care.
Really severe carapace damage can sometimes be repaired using special medical grade plastics and epoxy cements - ordinary fibreglass material is not usually suitable and should not be used. A few years ago one of our more memorable patients was a little terrapin which was found wandering with a severely cracked shell miles from the nearest water. This was successfully repaired by pinning the shell and cementing everything back into position with a medical epoxy compound. Fortunately, the back legs, although very weak, remained usable indicating that terminal spinal damage had not occurred. Fortunately this very lucky little turtle went on to make a complete recovery despite incurring what at first looked like dreadful and quite probably fatal damage.