Your knee is an important part of your body and you should not take any chances with it. it would be wise to have it checked out Rather then leave it to chance.
Probably cancer...
Insect bite possibly. Allergy reaction? If you are concerned about it then you should consult a doctor asap.
Yes, you may have cancer?
If it is to swollen it might have an infection otherwise it should be fine
You should be concerned about indoor air quality when you use AC. Old filters can let particulates into the air, making conditions like asthma worse.
The swelling should go down over the next few weeks. If you are at all concerned - go see your GP - he'll reassure you, and check everything's okay.
you smash the forehead swollen with a tool and the swollen will go away and you will have your normal forehead back.
If you are talking about wireless, no you do not need to worry about that.
Try watching the Disney Imagineers educational video on energy. Should answer your question.
Two or three days. We really can't help you if we can't see your ear and HOW swollen it is. But piercings are not supposed to be red, agitated looking, swollen, pussing, etc. There is a healthy amount of crusting but it should not be all red and irritated. Go back to your piercer if you're concerned. If you got it done at a mall with a gun, well then, there's your problem right there (since piercing guns are so horrible and bad for you that they should be illegal...)
Usually, ice. It might depend on why it's swollen, though. If it is swollen from a sting or an allergic reaction, an ointment would be better.
You should be concerned. Because without it no life would be there on earth.