Laser tattoo removal gone really bad and took to much time (Photo)

I've been doing my laser tattoo removal on black grey half bottom tattoo of my arms. It is already maybe the 7th times. But just one thin line that is make me sick and depressed. it doesnt wanna go away. And when right after I done the trearment, they became swollen really bad and burned. What should I do to treat the after trtment, and is it normal if they are become "darken". Please help