Tattoo removal side effects, all the black ink turned brown will this go away or can it be treated? (Photos)

I’ve had 7x treatments to remove black cover up tattoo. On first one I noticed all black shading turned brown, this has been said to be hyperpigmentation and remaining ink, it has improved slightly over tone with only 3x treatments targeting brown areas. does anyone know for certain what this is and how best to treat? Also, on 7th session with PicoSure laser I noticed I’ve lost a sufficient amount of pigment on top part of my arm, would this be something that can go back to normal?