If your are very concerned about your symptoms and are not sure if you have actually been bitten by something, you should see a doctor right away.   What does your rash look like? Is it Hives (see pictures)? Or does it look more like contact dermatitis (see pictures)?   It can be hard to tell. But hives generally result as an allergic reaction and look like red welts. Contact dermatitis can involve inflammation resulting from contact with acids, alkaline materials such as soaps and detergents, solvents, or other chemicals. The reaction usually resembles a burn.   If it's spread all over your body, then it may be hives. Hives may also be a sign of anaphylaxis, a potentially deadly allergic reaction. Other symptoms of anaphylaxis include:   * Difficulty breathing * Wheezing * Abnormal (high-pitched) breathing sounds * Confusion * Slurred speech * Rapid or weak pulse * Blueness of the skin (cyanosis), including the lips or nail beds * Fainting, light-headedness, dizziness* Anxiety or a feeling of "impending doom" * Heart palpitations * Nausea, vomiting * Diarrhea * Abdominal pain or cramping * Skin redness * Nasal congestion * Cough   Don't panic. See your doctor. If the rash has subsided by now, or if you haven't experienced any of these other symptoms, then you should be fine.