Last last month i have a dengue and now its already gone but im just thinking after a month my skin always itch, dunno why can it be the after effect?

Pruritis: Have you had your liver function tests done. Dengue may include hepatic involvement and elevated bilirubin levels may produce pruritis (itching). There are other causes which may or may not be related to your episode of dengue or you may well have acquired something along with the dengue. Go back and see the obviously astute doctor who diagnosed and treated you.