What can be done to stop my nettle stings from itching so much?

Itch: For stings and bites, cortisones are usually used to reduce inflammation and itch. You could try otc cortisone and if not better see your doctor for a prescription strength one.

Remedies for nettles: Wash the skin with soap & water. Make a paste of baking soda and water (sticky consistency) and spread over the affected area. In a pinch you can spit on the affected area because saliva can neutralize the chemical irritants. In the woods – apply mud to the area. Curly dock can also be rubbed on the area.