You can get temporary relief from the medication called Bendryl. You can get it at any grocery store or Pharmacy. If your swelling does not go down you should go to the emergency room or your doctor in order to get the swelling down. It can be dangerous for you to be so swollen.
If the allergic reaction was not caused by it, you can take Benadryl for most allergic reactions, and it should help the swelling as well. You may see it listed as Diphenhydramine as well. I'd also check with your Doctor on the swelling if it doesn't go down.