Insect Bite Remedies

I felt something sting my arm, I could feel the legs grab my arm when it did. It felt like when you touch an electric fence. I didn't see the wasp. There was a shallow bite about an eighth inch across. It itched a lot and began to swell till there was a red area around it the size of a silver dollar after a few days. I decided it wasn't going away on it's own so I rubbed tea tree oil into it and immediately after pure eucalyptus essential oil. It was gone in two or three days.