My daughter is on an allergy shot maintenance program and had her monthly shot this afternoon.  Around 2 hours later she was complaining that her arm was sore.  Now 7 hours later, it continues to be sore, is red, hard and swollen.  Would antihistamine be helpful at this point?  Interesting, she has had shots now for close to 2 years, and this is the first reaction.  Appreciate knowing if medication will help her through the night.  Thank you.  Karen
There can be any reaction at any time suddenly you can use anti-allergic, or antihistamine tb apply anti-allergic ointment if there is still problem can use short course of steroids