Make sunburn stop hurting?

As a trained first aid individual, if the burn is severe, I would suggest visiting the a medical professional as your friend could have second degree burns. If her skin develops warts and blisters this could be a sign of second degree burn. As a quick fix, I recommend you apply ice(not directly, put a clothe in between the ice and skin), more aloe vera and various other appropriate creams. However, if you are going to go through the trouble of obtaining all these creams, I think you might as well pay a visit to a doctor, clinic or hospital.