Husband's been getting allergy shots at the ENT and today we started the second-to-last vial. He got the jab in the office and they had him wait 30 minutes to monitor his reaction. After 30 minutes the nurse lady said he had a welt but it was smaller than a dime so he could go home, and she said if it gets bigger than a dime to do something but I can't remember what that something was and now it's the size of a mango.

✔️ he took a Benadryl before the appointment
✔️ he has an EpiPen
✔️ he's been icing it off & on since this afternoon when it was the size of a silver dollar
✔️ he took another Benadryl just now ✔️ he says it's really painful (50/50 on whether that means he's mildly uncomfortable or he has a life-threatening blood clot)

Do I need to, like, drive him to the emergency room? He's not having any problems breathing or anything, it's just this welt is getting SO BIG and I don't know when I should panic or what could happen if I don't. Help?