Patch backfall?

[zingo]

Planning to self-level a small bathroom for the first time. I've read up well but realize that things can go wrong, and I might end up with poor slope or even reverse slope in a corner. Can one then "patch" the reverse slope afterwards, i.e., apply an extra layer to compensate and fill where it went wrong? Or is it a sin in the self-leveling business? And if so, why?
:x

 

[Stefan N]

Prima and take another spin.

 

[PCLarsson]

Spackling is easier if it is a minor flaw...

 

[zingo]

Lovely. Thank you!

 

[cecar33]

But with filler from the same manufacturer, and for the purpose, as well as primer.

 

[GoForIt]

And don't forget to make sure that all small cracks in joints etc. are sealed, so the screed doesn't disappear that way..