Hello guys,
I thought I'd come and update. I immediately replaced the talcum powder with corn starch, and in a couple of days I noticed the itch was there, but much more bearable. Now, it's almost over, and there's none most of the time. The red has become pinkish. On top of that, I finally had to see the doc sooner than I had foreseen because I had to go and fetch a prescription to buy my mother's medicines, and since we share the doctor and -very uncharacteristically- he seemed relaxed and chatty, and no one else was in the queue to see him, I asked him and he could see my rash in all its splendour. He said he didn't think it was a matter of fungus, he told me that either talcum powder or corn starch (which I had already started using) would probably fix it, and that I should visit him again if it wasn't so in three-four days. He even said that considering how sensitive my skin is, it was no wonder the rash had set in with all this heat and sweat.
I have never worn any underwear which is not cotton. Even before being aware that my skin cannot tolerate as many things as other people's, I had sort of an aversion to synthetic clothes in general. I will try the merino wool, if I ever see some which is very thin (seeing how prone I am to sweating, the last thing I want is something that makes me warmer). As for hemp cloth, I hadn't heard of it, though I've been looking it up. I'll see... It's a bit weird to go and see a seamstress and ask her to make some knickers for you... Or maybe not! I'll try these options, and if I see they aren't better than cotton, I'll carry on as usual. After all, in all these decades I had never had this problem (probably because I hadn't had to put up with these temperatures for so long before).
So, once again, thanks a lot for being so helpful! After a summer in the dry dock I'm looking forward to my next dives in a couple of weeks, and I hope I won't have to get ashamed because of my red bosom and groins because they will be completely white again.