What Is The Treatment For Red Itchy Spots In The Body?

Hi,

My name is Maud, i have red itchy spots on my body, and they look like bites at first, but they get bigger and they start extending into a round ring and my skin is slightly grey in the centre of that ring, and its all on the soft part of my skin on my body, for example on my stomach, thihgs, under my arm and the back of my thighs and they are spreading like wild fire.

Please help