When a bee stings it leaves down the venom sack with the barb in the skin. The sting causes allergic reactions to us.When a bee stings it leaves down the venom sack with the barb in the skin. The sting causes allergic reactions to us <a href="http://www.boldsky.com/health/wellness/2014/how-to-treat-a-bee-sting-20140428100151-039666.html" target="_blank">Know More</a>.