Did I get cellulitis from an allergy test?

Patient: Do I need antibiotics? An hour after I had my allergy test I noticed that the redness and swelling was going down or gone at most of the test sites on my arm, except one site that was actually getting worse (more widespread, red, and swollen). I called the immunology office and they told me it was normal for the area to get a little more red and swollen and told me to take some benadryl. But even after taking 50mg of benadryl, the red spot that was initially about 1 cm in size, grew to about 5 inches in diameter, wrapping around and covering half of my forearm and the swelling was starting to cause muscle pain. Now, about 27 hours later, the swelling is down, and the redness is a deep in color, and the pain is subsiding, but the area is still quite numb and the reddened area has not reduced in size at all.

Symptoms: Redness, swelling, some numbness, skin warming, muscle pain