Battery pack a little bit damaged. Should I throw it out or repair?
LiFePO4 is a fairly safe chemistry and can take more abuse than most. The electrode material is far more stable than that used in LiPo/Li-ion cells, and most if not all incidents are electrical (i.e. short circuits leading to fire) rather than chemical in nature.

Nonetheless exposed metal surfaces should be insulated using a generous layer of silicone caulking or similar material (certainly not "liquid wire", since such a liquid is actually conductive). For additional protection the entire battery pack should then be placed in a silicone or rubber sleeve in order to provide further protection.