Talk to Dermatologist on A Light Brown Streak On Nail

I had come across a bruise on my toenail in the beginning of January with no known trauma. now, it's been 3 months and it has neither growed nor healed. Moreover, I have developed a light brown streak on my thumb a few days back . I suspect it to be subungual melanoma. I'll go to doctor in a few days but plz advice me should I ask my doctor to conduct biopsy to get everything clear. I am so terrified that I haven't even shared it properly with my family.