Soap actually increases his chance of survival in this scenario. Clean wound == less chance of infection.

Explaining what soap does and why people should value it would be the real challenge. Communication in general would need to be built from scratch. No english, no latin languages, no modern gestures like thumbs up and hand shakes, no common ground.

Depending on the era, I would bet on agriculture and fermentation as my empire-building tech. Wine first, then bread which is a little bit harder. Maybe spices also, I heard some pretty large empires were built on the power of funny flavors.

It's kind of funny that you think you would be able to produce wine 100,000 years ago. Do you know what grapes used to look like back then? Well, they were absolutely not the giant balls of sweetness we see today :D. They became that after thousands of years of selection by humans. Which first had to "invent" agriculture, which was not easy and it's still quite unclear whether the earliest civilizations that adopted it were better off until they actually became capable of creating large city-states which could then go on to dominate all their neighbours and started accumulating power.

So, 100,000 years ago you would need to convince people to join you in this crazy agriculture thing without any metal tools.... without domesticated animals either, by the way... as that would still be thousands of years in the future...

Finally, just taking a large amount of food and leaving it for a long time to ferment somewhere well protected, while everyone around is hungry, would be a huge challenge already. You might need to protect it both from people and from very large wild animals that had not gone extinct yet and would love to take that food from you (and likely use you as food also).

It doesn't need to be fine wine from the best grapes. It doesn't even need to be from grapes. The first beers were murky, slurry and not cold and people loved it.

I can convince my first followers by doing the first crops and batches myself, alone.

Usage of animals and metal tools in agriculture came much later. I don't need that to start. I just need fire and ceramics.

Of course it wouldn't be _easy_. Empires are never easy.

Ultimately, what I'm saying is the context of the original comment about soap: food tech would be more succesful than soap tech.

Elderberry would be my choice - it has medicinal properties as well as being an enjoyable flavour, it's essentially unchanged in the history that we've known of it (5000 years), so wine production techniques won't have to change much, and it's a fairly fast growing tree/shrub so building up a large orchard won't be a big deal.