The stinger should be removed as soon as possible by scraping it out, such as by using a finger nail or credit card. Squeezing the stinger, and attached venom pouch, may cause the release of more venom in to the skin.
Do not continue to scrape or irritate the sting area because you may actually push bacteria on the skin surface into the sting wound and start an infection. One particular potentially troublesome bacteria found on normal skin is Staphylococcus aureus, completely harmless and actually beneficial in maintaining a healthy balance on human skin, as long as it is not pushed into a skin wound. Under the skin, it can infect.