Very minor swelling at temple area of face ?

Possible allergic: Reaction. It could be airborne, food , contact etc. You may take some antihistamines in the meantime. To emergency room if it gets worst or you are having difficulty breathing, .

If its minor: I wouldn't worry, if it becomes real painful then get seen, mild temporal swelling without pain or trauma is not going to be an issue, unless it gets worse. See temporal arteritis if u want to worry yourself. Good luck.