any risks with numbing cream?

I am getting my 2nd laser treatment (with Cool Glide 1064 YAG) for my back. The first one really hurt (I belive levels were between 40-50).
The technician recommended an over the counter cream, Maxilene, that they would supply (for a nominal fee of course) that would help de-sensitise and numb the area.

Are there any concerns i should be worried about with using creams of this nature? I am worried - the area would be so numb, that I wouldnt be able to tell the technician if she is burning me and that she wouldnt know either. Is there anything i should watch out for? please help

I have some stuff on pain management here:

numbing cream could be dangerous when used on large areas like the entire back. so i wouldn’t do that.

I know how 40 to 50 can hurt, but I’d make sure they’re using the cool air machine like it is supposed to be used, and that the tech isn’t stopping the sweep motion, before I even would consider a topical numbing solution. And personally?? No, I wouldn’t consider it. The whole idea of topical numbing isn’t status quo. If it’s hurting you that much, and 50J is a good sized wallop of juice, then maybe you shouldn’t get treated that high. The pain may be a true indicator. Pay attention to it. My tech considers me Rambo when it comes to pain, and even I backed down from a 45J/50RF hit. No thanks. Just want to loose hair. Not hair and skin. It might lead to problems if you ignore that indicator.

My practitioner does not use numbing cream.