I went to the hospital yesterday and they took blood. the skin is red and stinging and a bruise has spread across my arm. should i wait it out?

Painful hematoma: Ice, elevation, decreased use, and minimal compression (ace wrap) should help improve your pain and bruising from a local hematoma. If symptoms do not improve in a day or two, seek medical evaluation.

Agree with Dr. D: If the bruise increases in size, it becomes more red, develops a discharge or it you get fever, see a doctor. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine