Red dot with white centre recurrent

[Medicine1988]

My body have those red dot pimple like very itchy and when those dot recurrent are very itchy - it turns larger than small dot little bit with white centre surrounding by red color. When it first started first time, verity itchy but not bump or dot, then start pop up bigger with hardening oval shape and look like tiny fluid in the middle.
When it healed, it will become dark flat spot like scar. It will recurrent the same spot with smaller red dot with white centre after 2-3 weeks.  
It appears around my leg, chest, waist, upper back, and abdomen.

I have no idea what is it.
Recurrent same spot over and over again been 6 months.