What is going on with my hard brake line

I did some extended braking and the Toyota brake hoses I installed 3 months ago appeared to have started leaking for some reason/ There is a coating o them that appears to have started leaking. What should I should I do?

 

I think I see tool marks on the nut. Seems this has been apart-'maybe careless handling dinged/bent the "flare" end and incorrect torque to reattach?

 

Considering the amount of visible contamination (fine dirt/sand particles) on those fittings I would take a fine wire brush and clean out the threads on the compression nut. Clear out the internal threads using a Q-tip. Any fibers left is an indication of thread damage which could lead to incorrect/insufficient torque when re-establishing connection between the fittings.

It is extremely important to keep every aspect of hydraulic fittings exceptionally clean when assembling.