Hello. I Have A Mole In The Centre Of My

hello. i have a mole in the centre of my back. it has started to peel almost like little scabs but it has not bled or been knocked by anything. its also about the size of a 50c piece with smaller moles growing on top of it. my doctor was meant to check it every 3 months but every time i get them to they say nothing is wrong with it. it has not been biopsied or anything. so my question is what does the peeling signify? and should i be going back to my gp?