I worked at a college football game yesterday and i burned the back of my knees and it really hurts. how would i treat this?

Sunburn: Sunburn is a real burn. That's why doctors encourage sunblock. But you can make it feel better while you're waiting for it to heal. Try Ibuprofen (if you can tolerate it), over-the-counter Hydrocortisone ointment, soaks in oatmeal bath, and an anti-itch cream that contains menthol and/or pramoxine. If you backed into a grill and you have blisters, see a doctor.