The stinger needs to come out, but it shouldn't be too difficult. You can use your fingernail or anything thin and blunt to gently pry it out. Don't use tweezers or anything that might squeeze. When bees like this sting, they usually leave behind a venom sack that will only inject more venom if you squeeze the stinger.

Once the stinger is out, clean the sting with soap and water. Is she having any trouble breathing or swallowing?