Sunburn

About five days ago, I got a serious sunburn on the entire back of my legs. The place where my bathing suit ended was purple and then moved into a dark red as the burn moved down my legs. The place where the burn affected me the most was my ass. After a few days of putting aloe on my legs and moisturizers, the right leg started to feel better and less painful. On the other hand, my left ass cheek has become completely raw to the point where I can not sit down or lay on the left side. I am unable to walk without a slight limp due to the severity of the pain and the raw section has begun to bleed. I have put cream on the raw area, however, it stings very badly and I am beginning to feel nauseous. Any suggestions on what I should do?