I am so sorry that you are dealing with this. I know it must be stressful not having an answer.
While we can't diagnose, we can speak from our own experience. I would suggest that you check with a dermatologist if possible or see your family doctor. The fact that it is definitely a new spot and appeared suddenly makes it something worth mentioning to a doctor.
I am including an article that may come in handy as you perform self-checks. It gives a simple breakdown of what to look for when you are examining your skin on a regular basis and noting changes.
https://skincancer.net/clinical/abcdes-melanoma
We are here for you any time. Don't hesitate to reach out to us. Wishing you all the best as you look for an answer!
April, SkinCancer.net, Moderator