What is the difference between psoriasis and eczema?

My guess is you have eczema a.k.a. dermatitis. Psoriasis is usually constant, more intense, usually involves a lot of flaking, and can be very widespread. From what you describe it sounds like an occasional localized flare-up, so that’s why I think it’s dermatitis. If this is a rare or one-time occurance, I’m thinking contact dermatitis, meaning you rubbed your thigh against an irritant. If it happens regularly, it may be atopic, meaning it’s most likely triggered by pollen, weather, or food.

Try keeping it moisturized. You may have to experiment with different products to find the one best suited for your skin. If you’re not going to see a doctor, try any of the various OTC steroid-based creams and ointments out there.