What Is The Indent On The Wrist?

Hello, My names sabrina Im 19 years old and 4ft 11in. Im conserned about my right arm on my wrist I tend to have an indent as if i left a rubber band on my wrist now its dented. When it first formed which was in September 09 it was a rash it was itchy then i woke up the next day the indent was there i also have one on my lower forearm please tell me what this is is it serious please Thanks?