How To Treat Itchy Rashes On Arms And Lower Back After A Wasp Sting On Chest?

hi a few weeks back i was stung by a wasp on my chest, there is still a re circle there about 14 cm , after a few days I had an itchy rask on my arms both sides , a few more day and the rash moved onto my sides and lower back, not it is on my bottom and upper legs. iTs itches more at night, if I drink something hot or have a glass of wine. I have tried a number of creams from chemist and antihistamine. Nothing to date has worked