I Had A Skin Allergy Week Ago.. It Was Wired

I had a skin allergy week ago..
It was wired because it appeared for very short time and then just disappeared also I noticed that whenever I washed any part of my body it started allerging all over the body or might be because of dryness..
Now I'm noticing black spots all over my body including face..
What's the reason behind this even though I never scratch it..