What Causes Red Swollen Area On Forearm After TB Test?

i recently received a tb 2 step, i was administered my first test wed. 3-2-11, and went back friday 3-4-11 for the reading of the first test, i asked when i should come back for the second administration and they said they would do it that same day, i now have a red swollen area on my forearm, it is a little irritating and warm to the touch, should i be worried about this, i thought there was suppose to be a seven day period between the first and second test of the two step?