Thats what happens when powering the lights from a P2. Because there are no fuses (Which helps in cost) most of us power the lights externally and use the P2 for earth reference and clock & data output. No wire gets connected to the P2's power out to pixels
Looks like you cooked the +v track as the design of the P2 is not to supply the power through the board but instead supply the power seperatly and connect the data, clock and ground only from the P2 output to the pixels, you then connect the grounds together and connect the +v at the pixels.
The reason for this is the P2 is a budget orientated controller which has lots of processing capabilaties but as far as power capabilities this was one of the trade offs to make them low in cost. So by connecting the P2 the way described above you should still be able to use the P2 as thats the way it was really intended to be connected all along.