Wounds leaving a dark marks behind.

A year ago, I started noticing that every wound I had would leave a dark mark behind. Even scratches left marks. My acne particularly concerned me. My acne would usually dry up, scab, and leave no mark behind. None of my wounds are scabbing the same way they usually did. Now, I have hyperpigmentation all over my body. My nails and hair have also significantly stopped growing. They typically grow fast. My doctor does not want to do more blood tests on me and has already tested me for b12, vitamin d, anemia, and thyroid. My vitamin d has recently been corrected. Along with skin issues, I am also dealing with severe depression and trouble falling asleep. I have periods where I sweat excessively, especially when I lie down. I'd like to know if this could have anything to do with my diet since i've lost my appetite. What could I be missing? Are there any other lab tests I can request?