How to fight wickback? Pls advise course of action

You should do a light rinse clean with no chemical turn down the PSI to maybe 200 and dry it with about four to five Strokes and you should be fine

Re clean the area rug with fiber rinse and they try to dry it as quick as you can. Take a airmover with you. Then after you are done flip the rug upside down and float it with the airmover to dry the fiber fast and any wicking will go to the base of the rug not the top.

Maybe see if she will let you take it back with you to redo it. This is easy to do at home in your garage and monitor the results.

Be carefull on cleaning with to much Ph

Good luck!