If you run around the plains like a careless idiot, you will get crushed. Previous biomes let you get away with being loose. Time to bring your A game.

Keep your shield out to block deathsquitos and fulings. Upgrade to padded gear and max it out. Eat well; sausage should be the WORST food you allow yourself to eat. Stay in at night to avoid fuling death patrols.

The plains are dangerous. If you don't respect them, don't prepare for them, they will kill you.