I believe the tiny skin bumps on your arms and legs may be goose bumps because of extremes of temperatures or even emotions. It could also be an allergic reaction to something. If they do not disappear or start to itch, consult a doctor to make a diagnosis and advise you on the best course of action to make.
The most common thing would be an allergic reaction to a number of things such as: food, plants, detergent, body soap, pets, ect. Benedryl is commonly used for such allergies. If you are on other medications, contact your pharmacist to make certain its ok if you take this or any over the counter medications.