Just over two weeks ago I found a very small felt pea sized hard lump under my inner arm where it folds at the elbow best describes it 

the lump was moveable under the skin, didn’t hurt just felt odd. 
saw GP who said likely to be a cyst and referred me for scan 

description minor significance on notes 

however as we have private insurance I visited dermatologist in London 

Scan done  lump removed

it is 8mm which I understand is very small .No vascularity (blood supply) ? to lump but removed for biopsy immediately I panic !!’ Why a biopsy? 
the lump he said is NOT a cyst and not likely to grow back so please what is it??

my husband has prostate cancer so this is such a  worry

sleepless and scared