Two weeks ago I had blood drawn for thyroid check. The first attempt, on the underside of my forearm, was a fail- she got the vein, but the blood didn't flow. It left a big dark bruise. No surprises. Two days ago, the bruise, almost gone, felt itchy. It has felt itchy on and off, but this afternoon it was VERY itchy, and I noticed hives for the first time. Only where the bruise is. I do have a mild allergy to latex, and they didn't use any in drawing the blood. I have certainly washed plenty since then, so the wipe she used on my skin can't be the problem. Should I be worried, or should I take a benedryl?