Welcome to healthcare magic!
The newly appearing freckle
if is having irregular margins, increasing in size, painful, itchy, weeping fluid, inhomogenous color then it must be biopsied because it can be a malignant melanoma
Melanoma is a devastating disease and can become untreatable early in the course if not managed early
The risk and benefit equation favours the biopsy
heavily so I would say your Dermatologist
is absolutely right. I myself have seen people loosing life secondary to melanoma and mets.
I hope this advise would be helpful for you.
Still if you have any queries or doubts, please write me back,
I would be happy to solve them.
Wish you a great health!