What is the biology behind bee stings?

Venom is injected by: Venom is injected in to the body. Human defence response come in play which cause brief pain and then it fade away. Apply ice immediately and many people get relief in 15 monutes.

See below: Bee stings and other stings from the hymenoptera class usually cause only a "local reaction" with redness swelling and warmth and initial pain that fades. This is due to the vasoactive venom components in the sting. Occ, a llr (large local reaction) can occur where the area enlarges over 2-3 days and then resolves over 5-10 days. Rarely, a systemic reaction occurs, anaphylaxis, which can kill.