Ive got a swollen lump on the top back of my leg which came up on sunday, i thought it was a insect bite,it has been very painful and still is,today it now has gone like a purple colour on top of the swelling and is like a sting feeling with swelling round it,i applied antihistim cream on last 2days,went to chemist today and he has given me hydrcortison cream to pit on, he told me it dosnt look like a bite,ive been looking online at pics,do you think itcould be a horsefly? Or do you think i should take a vist to docs?