I use the 40% lactic acid peel, which is the one people recommend to start off with because it's not too strong. For me, I've definitely noticed a big improvement with my PIH. At first it didn't seem like anything happened, but when I took pictures and actually compared side by side I didn't realise what a difference it made!
I don't know how tough your skin is but I'd still say start off slow. If you go up too fast you might do some real damage. I also did get an initial break out, but not everyone does. I tend to break out a little when I switch products anyway. The first few times dried out my skin so make sure you keep moisturising