so i noticed some "stuff" on one of my 55-200mm lens the other day and i tried to blow it off by using a compressed can of air. that didn't work. instead it just pushed whatever it was across the lens and it left a streak. so i had the bright idea of using a tissue to dab at it. well that didn't go well because now the lens looks worse after just 1 dab. i think i might've rubbed away some of the coating on the lens. is it ok to just leave it there or should i look into buying a cleaning kit? i'm scared to mess with it again.