How to get rid of big indented scar from a blister (liquid nitrogen)? (Photo)

I got liquid nitrogen for little skin tag in between my eyes. It healed but left a scar, went back he suggested another liquid nitrogen treatment to get rid of it. Blister was huge, he said it would come off in 2 days, it didn't so I washed it off. Left a huge indent scar. Really dissapinted in my doctor's advice and now I have no idea what to do. It is hard to cover up, I just wanted my skin to feel even, now it's even worse! Please help! Any advice or thoughts would be much appreciated!!!