Prevention? See if you can figure out a pattern to where they are (near an orchard) and avoid that area? Long term effects - you could develop allergic reaction and have more serious effects. As a kid I had little reaction aside from the pain, some swelling and maybe itching later. Now, I am allergic and swell bad - finger sting = sta-puft marshmallow arm, as far as the elbow; face/neck sting = Epinephrine & emergency room. If you have a reaction, benadryl helps counter the histamine reaction in your body.