I Have a Medium Brown Birthmark on my Upper Lip. What's the Best Way to Get Rid of It?

An examination would be necessary to evaluate the lesion and determine whether it requires surgical excision. There are many different types of lesions and the diagnosis determines the treatment.

I know this answer will be unsatisfying, but there really is no way to tell without seeing you. There are many different kinds of brown spots and birthmarks. Some need to be excised and others can be treated by laser. And sometimes, the exam is not always clear and a biopsy may be needed to determine the diagnosis and dictate what might be the best treatment. See a Dermatologist.