Good or bad thing?

I've been taking metformin for 2 days and was wondering if it's working. I've had darker lines like this since I've started the metformin. Does this mean it's helping my body with ovulation. YES I KNOW IT'S NEGATIVE! My levels of testosterone are high and they said I probably have PCOS. That's why my gyno prescribed me metformin plus then he did blood work. What are your thoughts?