How To Get Rid Of Black Marks And Scars After Rash On Thighs?

Hi, i have have had a rash on my inner thigh area which thankfully has now been relieved. but the problem i pose to you is how do i get rid of the huge black mark and slight scars left behind from my hardcore scratching due to irritation. the initial rash was black with numerous small spots which when popped would leak out a yellow type fluid. the rash was torture as i could not stop scratching it even for one second. so if you could kindly aid me in the question initially asked, would be of great help. thanks in advance