Usually, you’ll stay at the doctor’s office for about 30 minutes after you get an allergy shot. That's to make sure you don't get side effects like itchy eyes, shortness of breath, a runny nose, or a tight throat. If you get these symptoms after you leave, go back to your doctor's office or to the nearest emergency room.

Redness, swelling, or irritation right around the site of the injection is normal. These symptoms should go away in 4 to 8 hours.