I have truncal hyperhidrosis and get a weird flushing feeling from my lower back to upper thighs when I sweat there. It feels like that area is overheating. It mainly feels like that around my tailbone area. I'm hoping that it is secondary hyperhidrosis and that I can cure it somehow (but I've had it since I was 12 so probably not). It feels very different from when I sweat on my hands and feet.