Suggest Medication For Skin Itchiness Specially At Back

hi i m seef from india i am facing very strainge kind of skin itching problem,now its been almost two months that i am facing this problem.when it first started it used to irritate me a lot n it was happening only when i changed the clothes i always change clothes just before some time of going to bed,after changing clothes within 5 minutes this itching used to start everywhere on my body(mainly on back area)very strainge kind of rashes it was like the area i was scratching used to get rashes.now after passing 1 and a half month i dont get any itching at all not even at the time changing clothes but now i am more worried because now what happens is that when i make line with an any object on my skin it just produces the same design,it not hurts me but offcose it bothers me a lot.plz tell me what is this i am facing?is this any serious disease?