I get an asymmetrical saddle sore as well. For me the solution came from changing my bike short padding. I went to a much thinner bike short padding and that solved all my issues.

I kept finding that the padding would slowly bunch up on the left side. So it could be that I need to adjust my seat left/right a bit, but just using a tri short padding eliminated my issues so I didn't pursue other options.

I also found riding in the rain made it worse.

Good luck. It's no fun.

I had similar problems for the last 3 years (doing IMs) and this year I've been virtually sore free.

Things I've done this year :
- Got a bike fit and saddle lowered about 10mm
- Use chamois cream on every ride
- Use sudocream after every ride
- When riding I'll consciously move around on the saddle every 10 minutes or so therefore removing any prolonged "hotspot".