Hi, ScottishGirl, and welcome!
In case you did use too much, or the chemical was not what was advertised, you might try raking or scraping an inch or two of soil away from the plant. Maybe it has not yet all dissolved and soaked deep into the root zone already.
Just go gently and slowly until you start to hit some roots, then stop! You don't want to give the plant any new stress.
But decide where you want to move that suspect soil TO! It's probably still extra-acid or extra-basic (which turns them blue).
