I am playing around with RGB LED strips. Right now, I'm trying to make a seven-segment digit (ultimate goal is something like this but I'm a long way off that right now). This is very much learning/prototyping stage. I'm using WS2812B strips from ebay, so only three wires (+5V, GND and Data). I checked before I cut and everything lit up as it should.

The strips are cut to size, laid out, and soldered back together in a figure 8. But it's my first time soldering something this fine solo, and I've clearly done something wrong as only a couple of segments light up. I've managed to probe with a multi meter and can see I have (or at least seem to have) 5V all around the circuit/figure 8. I think the issue is therefore with the data wire between segment 2 (working) and segment 3 (not working).

I've done the obvious (or at least, I think the obvious) and reheated and disconnected that connection, cleaned the pads with solder wick, tested the wire, and resoldered but still no dice.

Would appreciate any bright ideas or guidance to figure out what has gone wrong. I might have burned out the pad? Shorted something out when I tinned the pads? Is there a way of figuring out whether the issue is at the exit or entrance of a segment?

My soldering isn't great, but there aren't obviously great blobs of solder shorting out the pads.