My ear is infected still from my last stretcher, when can I put my smaller stretcher in?

At the start of this month I got a stretcher, but I stupidly agreed to go straight to a 4mm, when usually people start at 2mm. Anyway, my ear got grossly infected and still is. I was just wondering would it be OK if i put a 2mm stretcher in whilst it was infected or would that make it a lot worse?