I woke up to red mark on my arm and then it progressed to being kind of dry in the center, there's no pain or itchiness. what can it be?

Spot: it sounds like a mild possibly fungal infection I would suggest using a combination of an antifungal and hydrocortisone and if that makes it go away fine if not let someone see it and give you a definitive diagnosis

Visual DX: Hi, it’s hard to say without a picture but there is a great app that may be able to help you get a diagnosis without being seen in person by a dermatologist. The app is called VisualDX and is one of the best, if not the best out there. Many clinicians, including myself, use it. Just snap a photo and it gives you a list of possible diagnoses. Good luck!